Factor out language specials to separate files in compiler.

Add transfer special. */

Makefile

@@ -26,7 +26,7 @@ PREFIX?=/usr/local
 BINDIR=$(PREFIX)/bin
 VERSION=\"0.0.0-beta\"
 
-CFLAGS=-std=c99 -Wall -Wextra -I./include -I./libs -g -fsanitize=address -DDST_VERSION=$(VERSION)
+CFLAGS=-std=c99 -Wall -Wextra -I./include -I./libs -g -DDST_VERSION=$(VERSION)
 PREFIX=/usr/local
 DST_TARGET=dst
 DST_XXD=xxd
@@ -47,8 +47,8 @@ all: $(DST_TARGET)
 ###################################
 
 DST_CORE_SOURCES=$(addprefix core/,\
-				 abstract.c array.c asm.c buffer.c compile.c\
+				 abstract.c array.c asm.c buffer.c compile.c compile_specials.c\
-				 fiber.c gc.c math.c parse.c sourcemap.c string.c\
+				 fiber.c gc.c io.c math.c parse.c sourcemap.c string.c\
 				 stl.c strtod.c struct.c symcache.c table.c tuple.c util.c\
 				 value.c vm.c wrap.c)
 

README.md

@@ -2,24 +2,33 @@
 
 [![Build Status](https://travis-ci.org/bakpakin/dst.svg?branch=master)](https://travis-ci.org/bakpakin/dst)
 
-dst is a language and vm that is small and embeddable, has metaprogramming
+dst is a functional programming language and vm. It is a variant of
-facilities, can interoperate with C, and has enough features to make it
-a useful general purpose programming language. It is a variant of
 Lisp with several native useful datatypes. Some of the more interesting and
 useful features are first class functions and closures, immutable and mutable
 hashtables, arrays, and bytebuffers, macros (NYI), tail-call optimization,
-and continuations (coroutines, error handling). The runtime and bootstrapping
+and continuations (coroutines, error handling). The runtime and 
 compiler are written in C99, but should eventually be completely compatible
 with C89 compilers.
 
-As of July 2017, still WIP. While the basic runtime is in place, as are many
-native functions, several important features are still being implemented and
-defined, like the module system and macros.
-
 There is a repl for trying out the language, as well as the ability
 to run script files. This client program is separate from the core runtime, so
 dst could be embedded into other programs.
 
+## Features
+
+First class closures
+Garbage collection
+lexical scoping
+First class green threads (continuations)
+Mutable and immutable arrays (array/tuple)
+Mutable and immutable hashtables (table/struct)
+Mutable and immutable strings (buffer/string)
+Byte code interpreter with an assembly interface
+Proper tail calls for functional code
+Direct interop with C
+
+
+
 ## Compiling and Running
 
 Clone the repository and run:

core/abstract.c

@@ -24,7 +24,7 @@
 #include "gc.h"
 
 /* Create new userdata */
-void *dst_abstract(size_t size, const DstAbstractType *atype) {
+void *dst_abstract(const DstAbstractType *atype, size_t size) {
     char *data = dst_gcalloc(DST_MEMORY_ABSTRACT, sizeof(DstAbstractHeader) + size);
     DstAbstractHeader *header = (DstAbstractHeader *)data;
     void *a = data + sizeof(DstAbstractHeader);

core/compile.c

@@ -80,12 +80,12 @@ DstFopts dstc_getvalue(DstFopts opts, Dst key) {
 }
 
 /* Check error */
-static int dstc_iserr(DstFopts *opts) {
+int dstc_iserr(DstFopts *opts) {
     return (opts->compiler->result.status == DST_COMPILE_ERROR);
 }
 
 /* Allocate a slot index */
-static int32_t dstc_lsloti(DstCompiler *c) {
+int32_t dstc_lsloti(DstCompiler *c) {
     DstScope *scope = &dst_v_last(c->scopes);
     /* Get the nth bit in the array */
     int32_t i, biti, len;
@@ -113,7 +113,7 @@ static int32_t dstc_lsloti(DstCompiler *c) {
 }
 
 /* Free a slot index */
-static void dstc_sfreei(DstCompiler *c, int32_t index) {
+void dstc_sfreei(DstCompiler *c, int32_t index) {
     DstScope *scope = &dst_v_last(c->scopes);
     /* Don't free the pre allocated slots */
     if (index >= 0 && (index < 0xF0 || index > 0xFF) && 
@@ -124,7 +124,7 @@ static void dstc_sfreei(DstCompiler *c, int32_t index) {
 /* Allocate a local near (n) slot and return its index. Slot
  * has maximum index max. Common value for max would be 0xFF,
  * the highest slot index representable with one byte. */
-static int32_t dstc_lslotn(DstCompiler *c, int32_t max, int32_t nth) {
+int32_t dstc_lslotn(DstCompiler *c, int32_t max, int32_t nth) {
     int32_t ret = dstc_lsloti(c);
     if (ret > max) {
         dstc_sfreei(c, ret);
@@ -141,7 +141,7 @@ void dstc_freeslot(DstCompiler *c, DstSlot s) {
 }
 
 /* Add a slot to a scope with a symbol associated with it (def or var). */
-static void dstc_nameslot(DstCompiler *c, const uint8_t *sym, DstSlot s) {
+void dstc_nameslot(DstCompiler *c, const uint8_t *sym, DstSlot s) {
     DstScope *scope = &dst_v_last(c->scopes);
     SymPair sp;
     sp.sym = sym;
@@ -150,31 +150,6 @@ static void dstc_nameslot(DstCompiler *c, const uint8_t *sym, DstSlot s) {
     dst_v_push(scope->syms, sp);
 }
 
-/* Add a constant to the current scope. Return the index of the constant. */
-static int32_t dstc_const(DstCompiler *c, const Dst *sourcemap, Dst x) {
-    DstScope *scope = &dst_v_last(c->scopes);
-    int32_t i, len;
-    /* Get the topmost function scope */
-    while (scope > c->scopes) {
-        if (scope->flags & DST_SCOPE_FUNCTION)
-            break;
-        scope--;
-    }
-    /* Check if already added */
-    len = dst_v_count(scope->consts);
-    for (i = 0; i < len; i++) {
-        if (dst_equals(x, scope->consts[i]))
-            return i;
-    }
-    /* Ensure not too many constsants. */
-    if (len >= 0xFFFF) {
-        dstc_cerror(c, sourcemap, "too many constants");
-        return 0;
-    }
-    dst_v_push(scope->consts, x);
-    return len;
-}
-
 /* Enter a new scope */
 void dstc_scope(DstCompiler *c, int flags) {
     DstScope scope;
@@ -344,6 +319,31 @@ void dstc_emit(DstCompiler *c, const Dst *sourcemap, uint32_t instr) {
     }
 }
 
+/* Add a constant to the current scope. Return the index of the constant. */
+static int32_t dstc_const(DstCompiler *c, const Dst *sourcemap, Dst x) {
+    DstScope *scope = &dst_v_last(c->scopes);
+    int32_t i, len;
+    /* Get the topmost function scope */
+    while (scope > c->scopes) {
+        if (scope->flags & DST_SCOPE_FUNCTION)
+            break;
+        scope--;
+    }
+    /* Check if already added */
+    len = dst_v_count(scope->consts);
+    for (i = 0; i < len; i++) {
+        if (dst_equals(x, scope->consts[i]))
+            return i;
+    }
+    /* Ensure not too many constsants. */
+    if (len >= 0xFFFF) {
+        dstc_cerror(c, sourcemap, "too many constants");
+        return 0;
+    }
+    dst_v_push(scope->consts, x);
+    return len;
+}
+
 /* Load a constant into a local slot */
 static void dstc_loadconst(DstCompiler *c, const Dst *sourcemap, Dst k, int32_t dest) {
     switch (dst_type(k)) {
@@ -382,7 +382,7 @@ static void dstc_loadconst(DstCompiler *c, const Dst *sourcemap, Dst k, int32_t
 
 /* Realize any slot to a local slot. Call this to get a slot index
  * that can be used in an instruction. */
-static int32_t dstc_preread(
+int32_t dstc_preread(
         DstCompiler *c,
         const Dst *sourcemap,
         int32_t max,
@@ -425,7 +425,7 @@ static int32_t dstc_preread(
 }
 
 /* Call this to release a read handle after emitting the instruction. */
-static void dstc_postread(DstCompiler *c, DstSlot s, int32_t index) {
+void dstc_postread(DstCompiler *c, DstSlot s, int32_t index) {
     if (index != s.index || s.envindex > 0 || s.flags & DST_SLOT_CONSTANT) {
         /* We need to free the temporary slot */
         dstc_sfreei(c, index);
@@ -434,7 +434,7 @@ static void dstc_postread(DstCompiler *c, DstSlot s, int32_t index) {
 
 /* Move values from one slot to another. The destination must
  * be writeable (not a literal). */
-static void dstc_copy(
+void dstc_copy(
         DstCompiler *c,
         const Dst *sourcemap,
         DstSlot dest,
@@ -559,7 +559,7 @@ static void dstc_copy(
 }
 
 /* Generate the return instruction for a slot. */
-static DstSlot dstc_return(DstCompiler *c, const Dst *sourcemap, DstSlot s) {
+DstSlot dstc_return(DstCompiler *c, const Dst *sourcemap, DstSlot s) {
     if (!(s.flags & DST_SLOT_RETURNED)) {
         if (s.flags & DST_SLOT_CONSTANT && dst_checktype(s.constant, DST_NIL)) {
             dstc_emit(c, sourcemap, DOP_RETURN_NIL);
@@ -575,7 +575,7 @@ static DstSlot dstc_return(DstCompiler *c, const Dst *sourcemap, DstSlot s) {
 
 /* Get a target slot for emitting an instruction. Will always return
  * a local slot. */
-static DstSlot dstc_gettarget(DstFopts opts) {
+DstSlot dstc_gettarget(DstFopts opts) {
     DstSlot slot;
     if ((opts.flags & DST_FOPTS_HINT) &&
         (opts.hint.envindex == 0) &&
@@ -590,19 +590,13 @@ static DstSlot dstc_gettarget(DstFopts opts) {
     return slot;
 }
 
-/* Slot and map pairing */
-typedef struct SlotMap {
-    DstSlot slot;
-    const Dst *map;
-} SlotMap;
-
 /* Get a bunch of slots for function arguments */
-SlotMap *toslots(DstFopts opts, int32_t start) {
+DstSM *dstc_toslots(DstFopts opts, int32_t start) {
     int32_t i, len;
-    SlotMap *ret = NULL;
+    DstSM *ret = NULL;
     len = dst_length(opts.x);
     for (i = start; i < len; i++) {
-        SlotMap sm;
+        DstSM sm;
         DstFopts subopts = dstc_getindex(opts, i);
         sm.slot = dstc_value(subopts);
         sm.map = subopts.sourcemap;
@@ -612,11 +606,11 @@ SlotMap *toslots(DstFopts opts, int32_t start) {
 }
 
 /* Get a bunch of slots for function arguments */
-static SlotMap *toslotskv(DstFopts opts) {
+DstSM *dstc_toslotskv(DstFopts opts) {
-    SlotMap *ret = NULL;
+    DstSM *ret = NULL;
     const DstKV *kv = NULL;
     while (NULL != (kv = dst_next(opts.x, kv))) {
-        SlotMap km, vm;
+        DstSM km, vm;
         DstFopts kopts = dstc_getkey(opts, kv->key);
         DstFopts vopts = dstc_getvalue(opts, kv->key);
         km.slot = dstc_value(kopts);
@@ -629,8 +623,8 @@ static SlotMap *toslotskv(DstFopts opts) {
     return ret;
 }
 
-/* Push slots load via toslots. */
+/* Push slots load via dstc_toslots. */
-static void pushslots(DstFopts opts, SlotMap *sms) {
+void dstc_pushslots(DstFopts opts, DstSM *sms) {
     DstCompiler *c = opts.compiler;
     const Dst *sm = opts.sourcemap;
     int32_t i;
@@ -665,8 +659,8 @@ static void pushslots(DstFopts opts, SlotMap *sms) {
     }
 }
 
-/* Free slots loaded via toslots */
+/* Free slots loaded via dstc_toslots */
-static void freeslots(DstFopts opts, SlotMap *sms) {
+void dstc_freeslots(DstFopts opts, DstSM *sms) {
     int32_t i;
     for (i = 0; i < dst_v_count(sms); i++) {
         dstc_freeslot(opts.compiler, sms[i].slot);
@@ -674,163 +668,10 @@ static void freeslots(DstFopts opts, SlotMap *sms) {
     dst_v_free(sms);
 }
 
-DstSlot dstc_quote(DstFopts opts, int32_t argn, const Dst *argv) {
-    if (argn != 1) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "expected 1 argument");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    return dstc_cslot(argv[0]);
-}
-
-DstSlot dstc_var(DstFopts opts, int32_t argn, const Dst *argv) {
-    DstCompiler *c = opts.compiler;
-    DstFopts subopts;
-    DstSlot ret;
-    if (argn != 2) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "expected 2 arguments");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    if (!dst_checktype(argv[0], DST_SYMBOL)) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "expected symbol");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    subopts = dstc_getindex(opts, 2);
-    subopts.flags = opts.flags & ~DST_FOPTS_TAIL;
-    ret = dstc_value(subopts);
-    if (dst_v_last(c->scopes).flags & DST_SCOPE_TOP) {
-        DstCompiler *c = opts.compiler;
-        const Dst *sm = opts.sourcemap;
-        DstSlot refslot, refarrayslot;
-        /* Global var, generate var */
-        DstTable *reftab = dst_table(1);
-        DstArray *ref = dst_array(1);
-        dst_array_push(ref, dst_wrap_nil());
-        dst_table_put(reftab, dst_csymbolv("ref"), dst_wrap_array(ref));
-        dst_put(opts.compiler->env, argv[0], dst_wrap_table(reftab));
-        refslot = dstc_cslot(dst_wrap_array(ref));
-        refarrayslot = refslot;
-        refslot.flags |= DST_SLOT_REF | DST_SLOT_NAMED | DST_SLOT_MUTABLE;
-        /* Generate code to set ref */
-        int32_t refarrayindex = dstc_preread(c, sm, 0xFF, 1, refarrayslot);
-        int32_t retindex = dstc_preread(c, sm, 0xFF, 2, ret);
-        dstc_emit(c, sm,
-                (retindex << 16) |
-                (refarrayindex << 8) |
-                DOP_PUT_INDEX);
-        dstc_postread(c, refarrayslot, refarrayindex);
-        dstc_postread(c, ret, retindex);
-        /*dstc_freeslot(c, refarrayslot);*/
-        ret = refslot;
-    } else {
-        /* Non root scope, bring to local slot */
-        if (ret.flags & DST_SLOT_NAMED ||
-            ret.envindex != 0 ||
-            ret.index < 0 ||
-            ret.index > 0xFF) {
-            /* Slot is not able to be named */
-            DstSlot localslot;
-            localslot.index = dstc_lsloti(c);
-            /* infer type? */
-            localslot.flags = DST_SLOT_NAMED | DST_SLOT_MUTABLE;
-            localslot.envindex = 0;
-            localslot.constant = dst_wrap_nil();
-            dstc_copy(opts.compiler, opts.sourcemap, localslot, ret);
-            ret = localslot;
-        }
-        dstc_nameslot(c, dst_unwrap_symbol(argv[0]), ret); 
-    }
-    return ret;
-}
-
-DstSlot dstc_varset(DstFopts opts, int32_t argn, const Dst *argv) {
-    DstFopts subopts;
-    DstSlot ret, dest;
-    if (argn != 2) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "expected 2 arguments");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    if (!dst_checktype(argv[0], DST_SYMBOL)) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "expected symbol");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    dest = dstc_resolve(opts.compiler, opts.sourcemap, dst_unwrap_symbol(argv[0]));
-    if (!(dest.flags & DST_SLOT_MUTABLE)) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "cannot set constant");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    subopts = dstc_getindex(opts, 2);
-    subopts.flags = DST_FOPTS_HINT;
-    subopts.hint = dest;
-    ret = dstc_value(subopts);
-    dstc_copy(opts.compiler, subopts.sourcemap, dest, ret);
-    return ret;
-}
-
-DstSlot dstc_def(DstFopts opts, int32_t argn, const Dst *argv) {
-    DstCompiler *c = opts.compiler;
-    DstFopts subopts;
-    DstSlot ret;
-    if (argn != 2) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "expected 2 arguments");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    if (!dst_checktype(argv[0], DST_SYMBOL)) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "expected symbol");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    subopts = dstc_getindex(opts, 2);
-    subopts.flags &= ~DST_FOPTS_TAIL;
-    ret = dstc_value(subopts);
-    ret.flags |= DST_SLOT_NAMED;
-    if (dst_v_last(c->scopes).flags & DST_SCOPE_TOP) {
-        /* Global def, generate code to store in env when executed */
-        DstCompiler *c = opts.compiler;
-        const Dst *sm = opts.sourcemap;
-        /* Root scope, add to def table */
-        DstSlot envslot = dstc_cslot(c->env);
-        DstSlot nameslot = dstc_cslot(argv[0]);
-        DstSlot valsymslot = dstc_cslot(dst_csymbolv("value"));
-        DstSlot tableslot = dstc_cslot(dst_wrap_cfunction(dst_stl_table));
-        /* Create env entry */
-        int32_t valsymindex = dstc_preread(c, sm, 0xFF, 1, valsymslot);
-        int32_t retindex = dstc_preread(c, sm, 0xFFFF, 2, ret);
-        dstc_emit(c, sm,
-                (retindex << 16) |
-                (valsymindex << 8) |
-                DOP_PUSH_2);
-        dstc_postread(c, ret, retindex);
-        dstc_postread(c, valsymslot, valsymindex);
-        dstc_freeslot(c, valsymslot);
-        int32_t tableindex = dstc_preread(opts.compiler, opts.sourcemap, 0xFF, 1, tableslot);
-        dstc_emit(c, sm,
-                (tableindex << 16) |
-                (tableindex << 8) |
-                DOP_CALL);
-        /* Add env entry to env */
-        int32_t nameindex = dstc_preread(opts.compiler, opts.sourcemap, 0xFF, 2, nameslot);
-        int32_t envindex = dstc_preread(opts.compiler, opts.sourcemap, 0xFF, 3, envslot);
-        dstc_emit(opts.compiler, opts.sourcemap, 
-                (tableindex << 24) |
-                (nameindex << 16) |
-                (envindex << 8) |
-                DOP_PUT);
-        dstc_postread(opts.compiler, envslot, envindex);
-        dstc_postread(opts.compiler, nameslot, nameindex);
-        dstc_postread(c, tableslot, tableindex);
-        dstc_freeslot(c, tableslot);
-        dstc_freeslot(c, envslot);
-        dstc_freeslot(c, tableslot);
-    } else {
-        /* Non root scope, simple slot alias */
-        dstc_nameslot(c, dst_unwrap_symbol(argv[0]), ret); 
-    }
-    return ret;
-}
-
 /* Compile some code that will be thrown away. Used to ensure
  * that dead code is well formed without including it in the final
  * bytecode. */
-static void dstc_throwaway(DstFopts opts) {
+void dstc_throwaway(DstFopts opts) {
     DstCompiler *c = opts.compiler;
     int32_t bufstart = dst_v_count(c->buffer);
     dstc_scope(c, DST_SCOPE_UNUSED);
@@ -843,201 +684,99 @@ static void dstc_throwaway(DstFopts opts) {
     }
 }
 
-/*
+/* Compile a call or tailcall instruction */
- * :condition
+static DstSlot dstc_call(DstFopts opts, DstSM *sms, DstSlot fun) {
- * ...
+    DstSlot retslot;
- * jump-if-not condition :right
+    int32_t localindex;
- * :left
- * ...
- * jump done (only if not tail)
- * :right
- * ...
- * :done
- */
-DstSlot dstc_if(DstFopts opts, int32_t argn, const Dst *argv) {
     DstCompiler *c = opts.compiler;
     const Dst *sm = opts.sourcemap;
-    int32_t labelr, labeljr, labeld, labeljd, condlocal;
+    dstc_pushslots(opts, sms);
-    DstFopts leftopts, rightopts, condopts;
+    dstc_freeslots(opts, sms);
-    DstSlot cond, left, right, target;
+    localindex = dstc_preread(c, sm, 0xFF, 1, fun);
-    const int tail = opts.flags & DST_FOPTS_TAIL;
+    if (opts.flags & DST_FOPTS_TAIL) {
-    const int drop = opts.flags & DST_FOPTS_DROP;
+        dstc_emit(c, sm, (localindex << 8) | DOP_TAILCALL);
-    (void) argv;
+        retslot = dstc_cslot(dst_wrap_nil());
+        retslot.flags = DST_SLOT_RETURNED;
+    } else {
+        retslot = dstc_gettarget(opts);
+        dstc_emit(c, sm, (localindex << 16) | (retslot.index << 8) | DOP_CALL);
+    }
+    dstc_postread(c, fun, localindex);
+    return retslot;
+}
 
-    if (argn < 2 || argn > 3) {
+/* Compile a tuple */
-        dstc_cerror(c, sm, "expected 2 or 3 arguments to if");
+DstSlot dstc_tuple(DstFopts opts) {
+    DstSlot head;
+    DstFopts subopts;
+    const Dst *tup = dst_unwrap_tuple(opts.x);
+    /* Empty tuple is tuple literal */
+    if (dst_tuple_length(tup) == 0) return dstc_cslot(opts.x);
+    /* Symbols could be specials */
+    if (dst_checktype(tup[0], DST_SYMBOL)) {
+        const DstSpecial *s = dstc_special(dst_unwrap_symbol(tup[0]));
+        if (NULL != s) {
+            return s->compile(opts, dst_tuple_length(tup) - 1, tup + 1);
+        }
+    }
+    /* Compile the head of the tuple */
+    subopts = dstc_getindex(opts, 0);
+    subopts.flags = DST_FUNCTION | DST_CFUNCTION;
+    head = dstc_value(subopts);
+    return dstc_call(opts, dstc_toslots(opts, 1), head);
+}
+
+static DstSlot dstc_array(DstFopts opts) {
+    return dstc_call(opts, dstc_toslots(opts, 0), dstc_cslot(dst_wrap_cfunction(dst_stl_array)));
+}
+
+static DstSlot dstc_tablector(DstFopts opts, DstCFunction cfun) {
+    return dstc_call(opts, dstc_toslotskv(opts), dstc_cslot(dst_wrap_cfunction(cfun)));
+}
+
+/* Compile a single value */
+DstSlot dstc_value(DstFopts opts) {
+    DstSlot ret;
+    if (dstc_iserr(&opts)) {
         return dstc_cslot(dst_wrap_nil());
     }
-
+    if (opts.compiler->recursion_guard <= 0) {
-    /* Get options */
+        dstc_cerror(opts.compiler, opts.sourcemap, "recursed too deeply");
-    condopts = dstc_getindex(opts, 1);
+        return dstc_cslot(dst_wrap_nil());
-    leftopts = dstc_getindex(opts, 2);
-    rightopts = dstc_getindex(opts, 3);
-    if (argn == 2) rightopts.sourcemap = opts.sourcemap;
-    if (opts.flags & DST_FOPTS_HINT) {
-        leftopts.flags |= DST_FOPTS_HINT;
-        rightopts.flags |= DST_FOPTS_HINT;
     }
-    if (tail) {
+    opts.compiler->recursion_guard--;
-        leftopts.flags |= DST_FOPTS_TAIL;
+    switch (dst_type(opts.x)) {
-        rightopts.flags |= DST_FOPTS_TAIL;
+        default:
+            ret = dstc_cslot(opts.x);
+            break;
+        case DST_SYMBOL:
+            {
+                const uint8_t *sym = dst_unwrap_symbol(opts.x);
+                ret = dstc_resolve(opts.compiler, opts.sourcemap, sym);
+                break;
             }
-    if (drop) {
+        case DST_TUPLE:
-        leftopts.flags |= DST_FOPTS_DROP;
+            ret = dstc_tuple(opts);
-        rightopts.flags |= DST_FOPTS_DROP;
+            break;
+        case DST_ARRAY:
+            ret = dstc_array(opts); 
+            break;
+        case DST_STRUCT:
+            ret = dstc_tablector(opts, dst_stl_struct); 
+            break;
+        case DST_TABLE:
+            ret = dstc_tablector(opts, dst_stl_table);
+            break;
     }
-
+    if (opts.flags & DST_FOPTS_TAIL) {
-    /* Compile condition */
+        ret = dstc_return(opts.compiler, opts.sourcemap, ret);
-    cond = dstc_value(condopts);
-
-    /* Check constant condition. */
-    /* TODO: Use type info for more short circuits */
-    if ((cond.flags & DST_SLOT_CONSTANT) && !(cond.flags & DST_SLOT_REF)) {
-        DstFopts goodopts, badopts;
-        if (dst_truthy(cond.constant)) {
-            goodopts = leftopts;
-            badopts = rightopts;
-        } else {
-            goodopts = rightopts;
-            badopts = leftopts;
     }
-        dstc_scope(c, 0);
+    opts.compiler->recursion_guard++;
-        target = dstc_value(goodopts);
-        dstc_popscope(c);
-        dstc_throwaway(badopts);
-        return target;
-    }
-
-    /* Set target for compilation */
-    target = (!drop && !tail) 
-        ? dstc_gettarget(opts)
-        : dstc_cslot(dst_wrap_nil());
-
-    /* Compile jump to right */
-    condlocal = dstc_preread(c, sm, 0xFF, 1, cond);
-    labeljr = dst_v_count(c->buffer);
-    dstc_emit(c, sm, DOP_JUMP_IF_NOT | (condlocal << 8));
-    dstc_postread(c, cond, condlocal);
-    dstc_freeslot(c, cond);
-
-    /* Condition left body */
-    dstc_scope(c, 0);
-    left = dstc_value(leftopts);
-    if (!drop && !tail) dstc_copy(c, sm, target, left); 
-    dstc_popscope(c);
-
-    /* Compile jump to done */
-    labeljd = dst_v_count(c->buffer);
-    if (!tail) dstc_emit(c, sm, DOP_JUMP);
-
-    /* Compile right body */
-    labelr = dst_v_count(c->buffer);
-    dstc_scope(c, 0);
-    right = dstc_value(rightopts);
-    if (!drop && !tail) dstc_copy(c, sm, target, right); 
-    dstc_popscope(c);
-
-    /* Write jumps - only add jump lengths if jump actually emitted */
-    labeld = dst_v_count(c->buffer);
-    c->buffer[labeljr] |= (labelr - labeljr) << 16;
-    if (!tail) c->buffer[labeljd] |= (labeld - labeljd) << 8;
-
-    if (tail) target.flags |= DST_SLOT_RETURNED;
-    return target;
-}
-
-DstSlot dstc_do(DstFopts opts, int32_t argn, const Dst *argv) {
-    int32_t i;
-    DstSlot ret;
-    dstc_scope(opts.compiler, 0);
-    (void) argv;
-    for (i = 0; i < argn; i++) {
-        DstFopts subopts = dstc_getindex(opts, i + 1);
-        if (i != argn - 1) {
-            subopts.flags = DST_FOPTS_DROP;
-        } else if (opts.flags & DST_FOPTS_TAIL) {
-            subopts.flags = DST_FOPTS_TAIL;
-        }
-        ret = dstc_value(subopts);
-        if (i != argn - 1) {
-            dstc_freeslot(opts.compiler, ret);
-        }
-    }
-    dstc_popscope(opts.compiler);
     return ret;
 }
 
-/*
- * :whiletop
- * ...
- * :condition
- * jump-if-not cond :done
- * ...
- * jump :whiletop
- * :done
- */
-DstSlot dstc_while(DstFopts opts, int32_t argn, const Dst *argv) {
-    DstCompiler *c = opts.compiler;
-    const Dst *sm = opts.sourcemap;
-    DstSlot cond;
-    int32_t condlocal, labelwt, labeld, labeljt, labelc, i;
-    int infinite = 0;
-    (void) argv;
-
-    if (argn < 2) {
-        dstc_cerror(c, sm, "expected at least 2 arguments");
-        return dstc_cslot(dst_wrap_nil());
-    }
-
-    labelwt = dst_v_count(c->buffer);
-
-    /* Compile condition */
-    cond = dstc_value(dstc_getindex(opts, 1));
-
-    /* Check for constant condition */
-    if (cond.flags & DST_SLOT_CONSTANT) {
-        /* Loop never executes */
-        if (!dst_truthy(cond.constant)) {
-            return dstc_cslot(dst_wrap_nil());
-        }
-        /* Infinite loop */
-        infinite = 1;
-    }
-
-    dstc_scope(c, 0);
-
-    /* Infinite loop does not need to check condition */
-    if (!infinite) {
-        condlocal = dstc_preread(c, sm, 0xFF, 1, cond);
-        labelc = dst_v_count(c->buffer);
-        dstc_emit(c, sm, DOP_JUMP_IF_NOT | (condlocal << 8));
-        dstc_postread(c, cond, condlocal);
-    }
-
-    /* Compile body */
-    for (i = 1; i < argn; i++) {
-        DstFopts subopts = dstc_getindex(opts, i + 1);
-        subopts.flags = DST_FOPTS_DROP;
-        dstc_freeslot(c, dstc_value(subopts));
-    }
-
-    /* Compile jump to whiletop */
-    labeljt = dst_v_count(c->buffer);
-    dstc_emit(c, sm, DOP_JUMP);
-
-    /* Calculate jumps */
-    labeld = dst_v_count(c->buffer);
-    if (!infinite) c->buffer[labelc] |= (labeld - labelc) << 16;
-    c->buffer[labeljt] |= (labelwt - labeljt) << 8;
-
-    /* Pop scope and return nil slot */
-    dstc_popscope(opts.compiler);
-
-    return dstc_cslot(dst_wrap_nil());
-}
-
 /* Compile a funcdef */
-static DstFuncDef *dstc_pop_funcdef(DstCompiler *c) {
+DstFuncDef *dstc_pop_funcdef(DstCompiler *c) {
     DstScope scope = dst_v_last(c->scopes);
     DstFuncDef *def = dst_gcalloc(DST_MEMORY_FUNCDEF, sizeof(DstFuncDef));
     def->source = NULL;
@@ -1088,272 +827,6 @@ static DstFuncDef *dstc_pop_funcdef(DstCompiler *c) {
     return def;
 }
 
-/* Add a funcdef to the top most function scope */
-static int32_t dstc_addfuncdef(DstCompiler *c, DstFuncDef *def) {
-    DstScope *scope = &dst_v_last(c->scopes);
-    while (scope >= c->scopes) {
-        if (scope->flags & DST_SCOPE_FUNCTION)
-            break;
-        scope--;
-    }
-    dst_assert(scope >= c->scopes, "could not add funcdef");
-    dst_v_push(scope->defs, def);
-    return dst_v_count(scope->defs) - 1;
-}
-
-DstSlot dstc_fn(DstFopts opts, int32_t argn, const Dst *argv) {
-    DstCompiler *c = opts.compiler;
-    const Dst *sm = opts.sourcemap;
-    DstFuncDef *def;
-    DstSlot ret;
-    int32_t paramcount, argi, parami, arity, localslot, defindex;
-    const Dst *params;
-    const Dst *psm;
-    int varargs = 0;
-
-    if (argn < 2) {
-        dstc_cerror(c, sm, "expected at least 2 arguments to function literal");
-        return dstc_cslot(dst_wrap_nil());
-    }
-
-    /* Begin function */
-    dstc_scope(c, DST_SCOPE_FUNCTION);
-
-    /* Read function parameters */
-    parami = 0;
-    arity = 0;
-    if (dst_checktype(argv[0], DST_SYMBOL)) parami = 1;
-    if (parami >= argn) {
-        dstc_cerror(c, sm, "expected function parameters");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    if (dst_seq_view(argv[parami], &params, &paramcount)) {
-        psm = dst_sourcemap_index(sm, parami + 1);
-        int32_t i;
-        for (i = 0; i < paramcount; i++) {
-            const Dst *psmi = dst_sourcemap_index(psm, i);
-            if (dst_checktype(params[i], DST_SYMBOL)) {
-                DstSlot slot;
-                /* Check for varargs */
-                if (0 == dst_cstrcmp(dst_unwrap_symbol(params[i]), "&")) {
-                    if (i != paramcount - 2) {
-                        dstc_cerror(c, psmi, "variable argument symbol in unexpected location");
-                        return dstc_cslot(dst_wrap_nil());
-                    }
-                    varargs = 1;
-                    arity--;
-                    continue;
-                }
-                slot.flags = DST_SLOT_NAMED;
-                slot.envindex = 0;
-                slot.constant = dst_wrap_nil();
-                slot.index = dstc_lsloti(c);
-                dstc_nameslot(c, dst_unwrap_symbol(params[i]), slot);
-                arity++;
-            } else {
-                dstc_cerror(c, psmi, "expected symbol as function parameter");
-                return dstc_cslot(dst_wrap_nil());
-            }
-        }
-    } else {
-        dstc_cerror(c, sm, "expected function parameters");
-        return dstc_cslot(dst_wrap_nil());
-    }
-
-    /* Compile function body */
-    for (argi = parami + 1; argi < argn; argi++) {
-        DstSlot s;
-        DstFopts subopts = dstc_getindex(opts, argi + 1);
-        subopts.flags = argi == (argn - 1) ? DST_FOPTS_TAIL : DST_FOPTS_DROP;
-        s = dstc_value(subopts);
-        dstc_freeslot(c, s);
-    }
-    
-    /* Build function */
-    def = dstc_pop_funcdef(c);
-    def->arity = arity;
-    if (varargs) def->flags |= DST_FUNCDEF_FLAG_VARARG;
-    defindex = dstc_addfuncdef(c, def);
-
-    /* Instantiate closure */
-    ret.flags = 0;
-    ret.envindex = 0;
-    ret.constant = dst_wrap_nil();
-    ret.index = dstc_lsloti(c);
-
-    localslot = ret.index > 0xF0 ? 0xF1 : ret.index;
-    dstc_emit(c, sm,
-            (defindex << 16) |
-            (localslot << 8) |
-            DOP_CLOSURE);
-    
-    if (ret.index != localslot) {
-        dstc_emit(c, sm, 
-                (ret.index << 16) |
-                (localslot << 8) |
-                DOP_MOVE_FAR);
-    }
-
-    return ret;
-}
-
-/* Keep in lexographic order */
-static const DstSpecial dstc_specials[] = {
-    {"def", dstc_def},
-    {"do", dstc_do},
-    {"fn", dstc_fn},
-    {"if", dstc_if},
-    {"quote", dstc_quote},
-    {"var", dstc_var},
-    {"varset!", dstc_varset},
-    {"while", dstc_while}
-};
-
-/* Compile a tuple */
-DstSlot dstc_tuple(DstFopts opts) {
-    DstSlot head;
-    DstFopts subopts;
-    DstCompiler *c = opts.compiler;
-    const Dst *tup = dst_unwrap_tuple(opts.x);
-    int headcompiled = 0;
-    subopts = dstc_getindex(opts, 0);
-    subopts.flags = DST_FUNCTION | DST_CFUNCTION;
-    if (dst_tuple_length(tup) == 0) {
-        return dstc_cslot(opts.x);
-    }
-    if (dst_checktype(tup[0], DST_SYMBOL)) {
-        const DstSpecial *s = dst_strbinsearch(
-                &dstc_specials,
-                sizeof(dstc_specials)/sizeof(DstSpecial),
-                sizeof(DstSpecial),
-                dst_unwrap_symbol(tup[0]));
-        if (NULL != s) {
-            return s->compile(opts, dst_tuple_length(tup) - 1, tup + 1);
-        }
-    }
-    if (!headcompiled) {
-        head = dstc_value(subopts);
-        headcompiled = 1;
-        /*
-         if ((head.flags & DST_SLOT_CONSTANT)) {
-            if (dst_checktype(head.constant, DST_CFUNCTION)) {
-                printf("add cfunction optimization here...\n");
-            }
-        }
-        */
-    }
-    /* Compile a normal function call */
-    {
-        int32_t headindex;
-        DstSlot retslot;
-        SlotMap *sms;
-        if (!headcompiled) {
-            head = dstc_value(subopts);
-            headcompiled = 1;
-        }
-        headindex = dstc_preread(c, subopts.sourcemap, 0xFFFF, 1, head);
-        sms = toslots(opts, 1);
-        pushslots(opts, sms);
-        freeslots(opts, sms);
-        if (opts.flags & DST_FOPTS_TAIL) {
-            dstc_emit(c, subopts.sourcemap, (headindex << 8) | DOP_TAILCALL);
-            retslot = dstc_cslot(dst_wrap_nil());
-            retslot.flags = DST_SLOT_RETURNED;
-        } else {
-            retslot = dstc_gettarget(opts);
-            dstc_emit(c, subopts.sourcemap, (headindex << 16) | (retslot.index << 8) | DOP_CALL);
-        }
-        dstc_postread(c, head, headindex);
-        return retslot;
-    }
-}
-
-static DstSlot dstc_array(DstFopts opts) {
-    DstCompiler *c = opts.compiler;
-    const Dst *sm = opts.sourcemap;
-    DstSlot ctor, retslot;
-    SlotMap *sms;
-    int32_t localindex;
-    sms = toslots(opts, 0);
-    pushslots(opts, sms);
-    freeslots(opts, sms);
-    ctor = dstc_cslot(dst_wrap_cfunction(dst_stl_array));
-    localindex = dstc_preread(c, sm, 0xFF, 1, ctor);
-    if (opts.flags & DST_FOPTS_TAIL) {
-        dstc_emit(c, sm, (localindex << 8) | DOP_TAILCALL);
-        retslot = dstc_cslot(dst_wrap_nil());
-        retslot.flags = DST_SLOT_RETURNED;
-    } else {
-        retslot = dstc_gettarget(opts);
-        dstc_emit(c, sm, (localindex << 16) | (retslot.index << 8) | DOP_CALL);
-    }
-    dstc_postread(c, ctor, localindex);
-    return retslot;
-}
-
-static DstSlot dstc_tablector(DstFopts opts, DstCFunction cfun) {
-    DstCompiler *c = opts.compiler;
-    const Dst *sm = opts.sourcemap;
-    DstSlot ctor, retslot;
-    SlotMap *sms;
-    int32_t localindex;
-    sms = toslotskv(opts);
-    pushslots(opts, sms);
-    freeslots(opts, sms);
-    ctor = dstc_cslot(dst_wrap_cfunction(cfun));
-    localindex = dstc_preread(c, sm, 0xFF, 1, ctor);
-    if (opts.flags & DST_FOPTS_TAIL) {
-        dstc_emit(c, sm, (localindex << 8) | DOP_TAILCALL);
-        retslot = dstc_cslot(dst_wrap_nil());
-        retslot.flags = DST_SLOT_RETURNED;
-    } else {
-        retslot = dstc_gettarget(opts);
-        dstc_emit(c, sm, (localindex << 16) | (retslot.index << 8) | DOP_CALL);
-    }
-    dstc_postread(c, ctor, localindex);
-    return retslot;
-}
-
-/* Compile a single value */
-DstSlot dstc_value(DstFopts opts) {
-    DstSlot ret;
-    if (dstc_iserr(&opts)) {
-        return dstc_cslot(dst_wrap_nil());
-    }
-    if (opts.compiler->recursion_guard <= 0) {
-        dstc_cerror(opts.compiler, opts.sourcemap, "recursed too deeply");
-        return dstc_cslot(dst_wrap_nil());
-    }
-    opts.compiler->recursion_guard--;
-    switch (dst_type(opts.x)) {
-        default:
-            ret = dstc_cslot(opts.x);
-            break;
-        case DST_SYMBOL:
-            {
-                const uint8_t *sym = dst_unwrap_symbol(opts.x);
-                ret = dstc_resolve(opts.compiler, opts.sourcemap, sym);
-                break;
-            }
-        case DST_TUPLE:
-            ret = dstc_tuple(opts);
-            break;
-        case DST_ARRAY:
-            ret = dstc_array(opts); 
-            break;
-        case DST_STRUCT:
-            ret = dstc_tablector(opts, dst_stl_struct); 
-            break;
-        case DST_TABLE:
-            ret = dstc_tablector(opts, dst_stl_table);
-            break;
-    }
-    if (opts.flags & DST_FOPTS_TAIL) {
-        ret = dstc_return(opts.compiler, opts.sourcemap, ret);
-    }
-    opts.compiler->recursion_guard++;
-    return ret;
-}
 
 /* Initialize a compiler */
 static void dstc_init(DstCompiler *c, Dst env) {

core/compile.h

@@ -53,6 +53,12 @@ struct DstSlot {
     Dst constant; /* If the slot has a constant value */
 };
 
+/* Slot and map pairing */
+typedef struct DstSM {
+    DstSlot slot;
+    const Dst *map;
+} DstSM;
+
 /* Special forms that need support */
 /* cond
  * while (continue, break)
@@ -131,36 +137,108 @@ struct DstFopts {
 /* A grouping of optimizations on a cfunction given certain conditions
  * on the arguments (such as all constants, or some known types). The appropriate
  * optimizations should be tried before compiling a normal function call. */
-struct DstCFunctionOptimizer {
+typedef struct DstCFunOptimizer {
     DstCFunction cfun;
     DstSlot (*optimize)(DstFopts opts, int32_t argn, const Dst *argv);
-};
+} DstCFunOptimizer;
+
+/* A grouping of a named special and the corresponding compiler fragment */
 typedef struct DstSpecial {
     const char *name;
     DstSlot (*compile)(DstFopts opts, int32_t argn, const Dst *argv);
 } DstSpecial;
 
-/* An array of optimizers sorted by key */
+/****************************************************/
-extern DstCFunctionOptimizer dstcr_optimizers[255];
+
+/* Get a cfunction optimizer. Return NULL if none exists.  */
+const DstCFunOptimizer *dstc_cfunopt(DstCFunction cfun);
+
+/* Get a special. Return NULL if none exists */
+const DstSpecial *dstc_special(const uint8_t *name);
+
+/* Check error */
+int dstc_iserr(DstFopts *opts);
+
+/* Allocate a slot index */
+int32_t dstc_lsloti(DstCompiler *c);
+
+/* Free a slot index */
+void dstc_sfreei(DstCompiler *c, int32_t index);
+
+/* Allocate a local near (n) slot and return its index. Slot
+ * has maximum index max. Common value for max would be 0xFF,
+ * the highest slot index representable with one byte. */
+int32_t dstc_lslotn(DstCompiler *c, int32_t max, int32_t nth);
+
+/* Free a slot */
+void dstc_freeslot(DstCompiler *c, DstSlot s);
+
+/* Add a slot to a scope with a symbol associated with it (def or var). */
+void dstc_nameslot(DstCompiler *c, const uint8_t *sym, DstSlot s);
+
+/* Realize any slot to a local slot. Call this to get a slot index
+ * that can be used in an instruction. */
+int32_t dstc_preread(
+        DstCompiler *c,
+        const Dst *sourcemap,
+        int32_t max,
+        int nth,
+        DstSlot s);
+
+/* Call this to release a read handle after emitting the instruction. */
+void dstc_postread(DstCompiler *c, DstSlot s, int32_t index);
+
+/* Move value from one slot to another. Cannot copy to constant slots. */
+void dstc_copy(
+        DstCompiler *c,
+        const Dst *sourcemap,
+        DstSlot dest,
+        DstSlot src);
+
+/* Throw away some code after checking that it is well formed. */
+void dstc_throwaway(DstFopts opts);
+
+/* Generate the return instruction for a slot. */
+DstSlot dstc_return(DstCompiler *c, const Dst *sourcemap, DstSlot s);
+
+/* Get a target slot for emitting an instruction. Will always return
+ * a local slot. */
+DstSlot dstc_gettarget(DstFopts opts);
+
+/* Get a bunch of slots for function arguments */
+DstSM *dstc_toslots(DstFopts opts, int32_t start);
+
+/* Get a bunch of slots for function arguments */
+DstSM *dstc_toslotskv(DstFopts opts);
+
+/* Push slots load via dstc_toslots. */
+void dstc_pushslots(DstFopts opts, DstSM *sms);
+
+/* Free slots loaded via dstc_toslots */
+void dstc_freeslots(DstFopts opts, DstSM *sms);
+
+/* Store an error */
+void dstc_error(DstCompiler *c, const Dst *sourcemap, const uint8_t *m);
+void dstc_cerror(DstCompiler *c, const Dst *sourcemap, const char *m);
 
 /* Dispatch to correct form compiler */
 DstSlot dstc_value(DstFopts opts);
 
-/****************************************************/
-
-void dstc_error(DstCompiler *c, const Dst *sourcemap, const uint8_t *m);
-void dstc_cerror(DstCompiler *c, const Dst *sourcemap, const char *m);
-
 /* Use these to get sub options. They will traverse the source map so
  * compiler errors make sense. Then modify the returned options. */
 DstFopts dstc_getindex(DstFopts opts, int32_t index);
 DstFopts dstc_getkey(DstFopts opts, Dst key);
 DstFopts dstc_getvalue(DstFopts opts, Dst key);
 
+/* Push and pop from the scope stack */
 void dstc_scope(DstCompiler *c, int newfn);
 void dstc_popscope(DstCompiler *c);
+DstFuncDef *dstc_pop_funcdef(DstCompiler *c);
 
+/* Create a destory slots */
 DstSlot dstc_cslot(Dst x);
+
+/* Free a slot */
 void dstc_freeslot(DstCompiler *c, DstSlot slot);
 
 /* Search for a symbol */

core/compile_specials.c

@@ -0,0 +1,537 @@
+/*
+* Copyright (c) 2017 Calvin Rose
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to
+* deal in the Software without restriction, including without limitation the
+* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+* sell copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+* IN THE SOFTWARE.
+*/
+
+#include <dst/dst.h>
+#include <dst/dststl.h>
+#include "compile.h"
+#include "gc.h"
+#include "sourcemap.h"
+#include "util.h"
+
+DstSlot dstc_quote(DstFopts opts, int32_t argn, const Dst *argv) {
+    if (argn != 1) {
+        dstc_cerror(opts.compiler, opts.sourcemap, "expected 1 argument");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    return dstc_cslot(argv[0]);
+}
+
+DstSlot dstc_var(DstFopts opts, int32_t argn, const Dst *argv) {
+    DstCompiler *c = opts.compiler;
+    DstFopts subopts;
+    DstSlot ret;
+    if (argn != 2) {
+        dstc_cerror(opts.compiler, opts.sourcemap, "expected 2 arguments");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    if (!dst_checktype(argv[0], DST_SYMBOL)) {
+        dstc_cerror(opts.compiler, opts.sourcemap, "expected symbol");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    subopts = dstc_getindex(opts, 2);
+    subopts.flags = opts.flags & ~DST_FOPTS_TAIL;
+    ret = dstc_value(subopts);
+    if (dst_v_last(c->scopes).flags & DST_SCOPE_TOP) {
+        DstCompiler *c = opts.compiler;
+        const Dst *sm = opts.sourcemap;
+        DstSlot refslot, refarrayslot;
+        /* Global var, generate var */
+        DstTable *reftab = dst_table(1);
+        DstArray *ref = dst_array(1);
+        dst_array_push(ref, dst_wrap_nil());
+        dst_table_put(reftab, dst_csymbolv("ref"), dst_wrap_array(ref));
+        dst_put(opts.compiler->env, argv[0], dst_wrap_table(reftab));
+        refslot = dstc_cslot(dst_wrap_array(ref));
+        refarrayslot = refslot;
+        refslot.flags |= DST_SLOT_REF | DST_SLOT_NAMED | DST_SLOT_MUTABLE;
+        /* Generate code to set ref */
+        int32_t refarrayindex = dstc_preread(c, sm, 0xFF, 1, refarrayslot);
+        int32_t retindex = dstc_preread(c, sm, 0xFF, 2, ret);
+        dstc_emit(c, sm,
+                (retindex << 16) |
+                (refarrayindex << 8) |
+                DOP_PUT_INDEX);
+        dstc_postread(c, refarrayslot, refarrayindex);
+        dstc_postread(c, ret, retindex);
+        /*dstc_freeslot(c, refarrayslot);*/
+        ret = refslot;
+    } else {
+        /* Non root scope, bring to local slot */
+        if (ret.flags & DST_SLOT_NAMED ||
+            ret.envindex != 0 ||
+            ret.index < 0 ||
+            ret.index > 0xFF) {
+            /* Slot is not able to be named */
+            DstSlot localslot;
+            localslot.index = dstc_lsloti(c);
+            /* infer type? */
+            localslot.flags = DST_SLOT_NAMED | DST_SLOT_MUTABLE;
+            localslot.envindex = 0;
+            localslot.constant = dst_wrap_nil();
+            dstc_copy(opts.compiler, opts.sourcemap, localslot, ret);
+            ret = localslot;
+        }
+        dstc_nameslot(c, dst_unwrap_symbol(argv[0]), ret); 
+    }
+    return ret;
+}
+
+DstSlot dstc_varset(DstFopts opts, int32_t argn, const Dst *argv) {
+    DstFopts subopts;
+    DstSlot ret, dest;
+    if (argn != 2) {
+        dstc_cerror(opts.compiler, opts.sourcemap, "expected 2 arguments");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    if (!dst_checktype(argv[0], DST_SYMBOL)) {
+        dstc_cerror(opts.compiler, opts.sourcemap, "expected symbol");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    dest = dstc_resolve(opts.compiler, opts.sourcemap, dst_unwrap_symbol(argv[0]));
+    if (!(dest.flags & DST_SLOT_MUTABLE)) {
+        dstc_cerror(opts.compiler, opts.sourcemap, "cannot set constant");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    subopts = dstc_getindex(opts, 2);
+    subopts.flags = DST_FOPTS_HINT;
+    subopts.hint = dest;
+    ret = dstc_value(subopts);
+    dstc_copy(opts.compiler, subopts.sourcemap, dest, ret);
+    return ret;
+}
+
+DstSlot dstc_def(DstFopts opts, int32_t argn, const Dst *argv) {
+    DstCompiler *c = opts.compiler;
+    DstFopts subopts;
+    DstSlot ret;
+    if (argn != 2) {
+        dstc_cerror(opts.compiler, opts.sourcemap, "expected 2 arguments");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    if (!dst_checktype(argv[0], DST_SYMBOL)) {
+        dstc_cerror(opts.compiler, opts.sourcemap, "expected symbol");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    subopts = dstc_getindex(opts, 2);
+    subopts.flags &= ~DST_FOPTS_TAIL;
+    ret = dstc_value(subopts);
+    ret.flags |= DST_SLOT_NAMED;
+    if (dst_v_last(c->scopes).flags & DST_SCOPE_TOP) {
+        /* Global def, generate code to store in env when executed */
+        DstCompiler *c = opts.compiler;
+        const Dst *sm = opts.sourcemap;
+        /* Root scope, add to def table */
+        DstSlot envslot = dstc_cslot(c->env);
+        DstSlot nameslot = dstc_cslot(argv[0]);
+        DstSlot valsymslot = dstc_cslot(dst_csymbolv("value"));
+        DstSlot tableslot = dstc_cslot(dst_wrap_cfunction(dst_stl_table));
+        /* Create env entry */
+        int32_t valsymindex = dstc_preread(c, sm, 0xFF, 1, valsymslot);
+        int32_t retindex = dstc_preread(c, sm, 0xFFFF, 2, ret);
+        dstc_emit(c, sm,
+                (retindex << 16) |
+                (valsymindex << 8) |
+                DOP_PUSH_2);
+        dstc_postread(c, ret, retindex);
+        dstc_postread(c, valsymslot, valsymindex);
+        dstc_freeslot(c, valsymslot);
+        int32_t tableindex = dstc_preread(opts.compiler, opts.sourcemap, 0xFF, 1, tableslot);
+        dstc_emit(c, sm,
+                (tableindex << 16) |
+                (tableindex << 8) |
+                DOP_CALL);
+        /* Add env entry to env */
+        int32_t nameindex = dstc_preread(opts.compiler, opts.sourcemap, 0xFF, 2, nameslot);
+        int32_t envindex = dstc_preread(opts.compiler, opts.sourcemap, 0xFF, 3, envslot);
+        dstc_emit(opts.compiler, opts.sourcemap, 
+                (tableindex << 24) |
+                (nameindex << 16) |
+                (envindex << 8) |
+                DOP_PUT);
+        dstc_postread(opts.compiler, envslot, envindex);
+        dstc_postread(opts.compiler, nameslot, nameindex);
+        dstc_postread(c, tableslot, tableindex);
+        dstc_freeslot(c, tableslot);
+        dstc_freeslot(c, envslot);
+        dstc_freeslot(c, tableslot);
+    } else {
+        /* Non root scope, simple slot alias */
+        dstc_nameslot(c, dst_unwrap_symbol(argv[0]), ret); 
+    }
+    return ret;
+}
+
+/*
+ * :condition
+ * ...
+ * jump-if-not condition :right
+ * :left
+ * ...
+ * jump done (only if not tail)
+ * :right
+ * ...
+ * :done
+ */
+DstSlot dstc_if(DstFopts opts, int32_t argn, const Dst *argv) {
+    DstCompiler *c = opts.compiler;
+    const Dst *sm = opts.sourcemap;
+    int32_t labelr, labeljr, labeld, labeljd, condlocal;
+    DstFopts leftopts, rightopts, condopts;
+    DstSlot cond, left, right, target;
+    const int tail = opts.flags & DST_FOPTS_TAIL;
+    const int drop = opts.flags & DST_FOPTS_DROP;
+    (void) argv;
+
+    if (argn < 2 || argn > 3) {
+        dstc_cerror(c, sm, "expected 2 or 3 arguments to if");
+        return dstc_cslot(dst_wrap_nil());
+    }
+
+    /* Get options */
+    condopts = dstc_getindex(opts, 1);
+    leftopts = dstc_getindex(opts, 2);
+    rightopts = dstc_getindex(opts, 3);
+    if (argn == 2) rightopts.sourcemap = opts.sourcemap;
+    if (opts.flags & DST_FOPTS_HINT) {
+        leftopts.flags |= DST_FOPTS_HINT;
+        rightopts.flags |= DST_FOPTS_HINT;
+    }
+    if (tail) {
+        leftopts.flags |= DST_FOPTS_TAIL;
+        rightopts.flags |= DST_FOPTS_TAIL;
+    }
+    if (drop) {
+        leftopts.flags |= DST_FOPTS_DROP;
+        rightopts.flags |= DST_FOPTS_DROP;
+    }
+
+    /* Compile condition */
+    cond = dstc_value(condopts);
+
+    /* Check constant condition. */
+    /* TODO: Use type info for more short circuits */
+    if ((cond.flags & DST_SLOT_CONSTANT) && !(cond.flags & DST_SLOT_REF)) {
+        DstFopts goodopts, badopts;
+        if (dst_truthy(cond.constant)) {
+            goodopts = leftopts;
+            badopts = rightopts;
+        } else {
+            goodopts = rightopts;
+            badopts = leftopts;
+        }
+        dstc_scope(c, 0);
+        target = dstc_value(goodopts);
+        dstc_popscope(c);
+        dstc_throwaway(badopts);
+        return target;
+    }
+
+    /* Set target for compilation */
+    target = (!drop && !tail) 
+        ? dstc_gettarget(opts)
+        : dstc_cslot(dst_wrap_nil());
+
+    /* Compile jump to right */
+    condlocal = dstc_preread(c, sm, 0xFF, 1, cond);
+    labeljr = dst_v_count(c->buffer);
+    dstc_emit(c, sm, DOP_JUMP_IF_NOT | (condlocal << 8));
+    dstc_postread(c, cond, condlocal);
+    dstc_freeslot(c, cond);
+
+    /* Condition left body */
+    dstc_scope(c, 0);
+    left = dstc_value(leftopts);
+    if (!drop && !tail) dstc_copy(c, sm, target, left); 
+    dstc_popscope(c);
+
+    /* Compile jump to done */
+    labeljd = dst_v_count(c->buffer);
+    if (!tail) dstc_emit(c, sm, DOP_JUMP);
+
+    /* Compile right body */
+    labelr = dst_v_count(c->buffer);
+    dstc_scope(c, 0);
+    right = dstc_value(rightopts);
+    if (!drop && !tail) dstc_copy(c, sm, target, right); 
+    dstc_popscope(c);
+
+    /* Write jumps - only add jump lengths if jump actually emitted */
+    labeld = dst_v_count(c->buffer);
+    c->buffer[labeljr] |= (labelr - labeljr) << 16;
+    if (!tail) c->buffer[labeljd] |= (labeld - labeljd) << 8;
+
+    if (tail) target.flags |= DST_SLOT_RETURNED;
+    return target;
+}
+
+/* Compile a do form. Do forms execute their body sequentially and
+ * evaluate to the last expression in the body. */
+DstSlot dstc_do(DstFopts opts, int32_t argn, const Dst *argv) {
+    int32_t i;
+    DstSlot ret;
+    dstc_scope(opts.compiler, 0);
+    (void) argv;
+    for (i = 0; i < argn; i++) {
+        DstFopts subopts = dstc_getindex(opts, i + 1);
+        if (i != argn - 1) {
+            subopts.flags = DST_FOPTS_DROP;
+        } else if (opts.flags & DST_FOPTS_TAIL) {
+            subopts.flags = DST_FOPTS_TAIL;
+        }
+        ret = dstc_value(subopts);
+        if (i != argn - 1) {
+            dstc_freeslot(opts.compiler, ret);
+        }
+    }
+    dstc_popscope(opts.compiler);
+    return ret;
+}
+
+DstSlot dstc_transfer(DstFopts opts, int32_t argn, const Dst *argv) {
+    DstCompiler *c = opts.compiler;
+    const Dst *sm = opts.sourcemap;
+    DstSlot dest, fib, val;
+    int32_t destindex, fibindex, valindex;
+    (void) argv;
+    if (argn > 2) {
+        dstc_cerror(c, sm, "expected no more than 2 arguments");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    dest = dstc_gettarget(opts);
+    fib = (argn > 0) ? dstc_value(dstc_getindex(opts, 1)) : dstc_cslot(dst_wrap_nil());
+    val = (argn > 1) ? dstc_value(dstc_getindex(opts, 2)) : dstc_cslot(dst_wrap_nil());
+    destindex = dstc_preread(c, sm, 0xFF, 1, dest);
+    fibindex = dstc_preread(c, sm, 0xFF, 2, fib);
+    valindex = dstc_preread(c, sm, 0xFF, 3, val);
+    dstc_emit(c, sm, 
+            (valindex << 24) |
+            (fibindex << 16) |
+            (destindex << 8) |
+            DOP_TRANSFER);
+    dstc_postread(c, dest, destindex);
+    dstc_postread(c, fib, fibindex);
+    dstc_postread(c, val, valindex);
+    dstc_freeslot(c, fib);
+    dstc_freeslot(c, val);
+    return dest;
+}
+
+/*
+ * :whiletop
+ * ...
+ * :condition
+ * jump-if-not cond :done
+ * ...
+ * jump :whiletop
+ * :done
+ */
+DstSlot dstc_while(DstFopts opts, int32_t argn, const Dst *argv) {
+    DstCompiler *c = opts.compiler;
+    const Dst *sm = opts.sourcemap;
+    DstSlot cond;
+    int32_t condlocal, labelwt, labeld, labeljt, labelc, i;
+    int infinite = 0;
+    (void) argv;
+
+    if (argn < 2) {
+        dstc_cerror(c, sm, "expected at least 2 arguments");
+        return dstc_cslot(dst_wrap_nil());
+    }
+
+    labelwt = dst_v_count(c->buffer);
+
+    /* Compile condition */
+    cond = dstc_value(dstc_getindex(opts, 1));
+
+    /* Check for constant condition */
+    if (cond.flags & DST_SLOT_CONSTANT) {
+        /* Loop never executes */
+        if (!dst_truthy(cond.constant)) {
+            return dstc_cslot(dst_wrap_nil());
+        }
+        /* Infinite loop */
+        infinite = 1;
+    }
+
+    dstc_scope(c, 0);
+
+    /* Infinite loop does not need to check condition */
+    if (!infinite) {
+        condlocal = dstc_preread(c, sm, 0xFF, 1, cond);
+        labelc = dst_v_count(c->buffer);
+        dstc_emit(c, sm, DOP_JUMP_IF_NOT | (condlocal << 8));
+        dstc_postread(c, cond, condlocal);
+    }
+
+    /* Compile body */
+    for (i = 1; i < argn; i++) {
+        DstFopts subopts = dstc_getindex(opts, i + 1);
+        subopts.flags = DST_FOPTS_DROP;
+        dstc_freeslot(c, dstc_value(subopts));
+    }
+
+    /* Compile jump to whiletop */
+    labeljt = dst_v_count(c->buffer);
+    dstc_emit(c, sm, DOP_JUMP);
+
+    /* Calculate jumps */
+    labeld = dst_v_count(c->buffer);
+    if (!infinite) c->buffer[labelc] |= (labeld - labelc) << 16;
+    c->buffer[labeljt] |= (labelwt - labeljt) << 8;
+
+    /* Pop scope and return nil slot */
+    dstc_popscope(opts.compiler);
+
+    return dstc_cslot(dst_wrap_nil());
+}
+
+/* Add a funcdef to the top most function scope */
+static int32_t dstc_addfuncdef(DstCompiler *c, DstFuncDef *def) {
+    DstScope *scope = &dst_v_last(c->scopes);
+    while (scope >= c->scopes) {
+        if (scope->flags & DST_SCOPE_FUNCTION)
+            break;
+        scope--;
+    }
+    dst_assert(scope >= c->scopes, "could not add funcdef");
+    dst_v_push(scope->defs, def);
+    return dst_v_count(scope->defs) - 1;
+}
+
+DstSlot dstc_fn(DstFopts opts, int32_t argn, const Dst *argv) {
+    DstCompiler *c = opts.compiler;
+    const Dst *sm = opts.sourcemap;
+    DstFuncDef *def;
+    DstSlot ret;
+    int32_t paramcount, argi, parami, arity, localslot, defindex;
+    const Dst *params;
+    const Dst *psm;
+    int varargs = 0;
+
+    if (argn < 2) {
+        dstc_cerror(c, sm, "expected at least 2 arguments to function literal");
+        return dstc_cslot(dst_wrap_nil());
+    }
+
+    /* Begin function */
+    dstc_scope(c, DST_SCOPE_FUNCTION);
+
+    /* Read function parameters */
+    parami = 0;
+    arity = 0;
+    if (dst_checktype(argv[0], DST_SYMBOL)) parami = 1;
+    if (parami >= argn) {
+        dstc_cerror(c, sm, "expected function parameters");
+        return dstc_cslot(dst_wrap_nil());
+    }
+    if (dst_seq_view(argv[parami], &params, &paramcount)) {
+        psm = dst_sourcemap_index(sm, parami + 1);
+        int32_t i;
+        for (i = 0; i < paramcount; i++) {
+            const Dst *psmi = dst_sourcemap_index(psm, i);
+            if (dst_checktype(params[i], DST_SYMBOL)) {
+                DstSlot slot;
+                /* Check for varargs */
+                if (0 == dst_cstrcmp(dst_unwrap_symbol(params[i]), "&")) {
+                    if (i != paramcount - 2) {
+                        dstc_cerror(c, psmi, "variable argument symbol in unexpected location");
+                        return dstc_cslot(dst_wrap_nil());
+                    }
+                    varargs = 1;
+                    arity--;
+                    continue;
+                }
+                slot.flags = DST_SLOT_NAMED;
+                slot.envindex = 0;
+                slot.constant = dst_wrap_nil();
+                slot.index = dstc_lsloti(c);
+                dstc_nameslot(c, dst_unwrap_symbol(params[i]), slot);
+                arity++;
+            } else {
+                dstc_cerror(c, psmi, "expected symbol as function parameter");
+                return dstc_cslot(dst_wrap_nil());
+            }
+        }
+    } else {
+        dstc_cerror(c, sm, "expected function parameters");
+        return dstc_cslot(dst_wrap_nil());
+    }
+
+    /* Compile function body */
+    for (argi = parami + 1; argi < argn; argi++) {
+        DstSlot s;
+        DstFopts subopts = dstc_getindex(opts, argi + 1);
+        subopts.flags = argi == (argn - 1) ? DST_FOPTS_TAIL : DST_FOPTS_DROP;
+        s = dstc_value(subopts);
+        dstc_freeslot(c, s);
+    }
+    
+    /* Build function */
+    def = dstc_pop_funcdef(c);
+    def->arity = arity;
+    if (varargs) def->flags |= DST_FUNCDEF_FLAG_VARARG;
+    defindex = dstc_addfuncdef(c, def);
+
+    /* Instantiate closure */
+    ret.flags = 0;
+    ret.envindex = 0;
+    ret.constant = dst_wrap_nil();
+    ret.index = dstc_lsloti(c);
+
+    localslot = ret.index > 0xF0 ? 0xF1 : ret.index;
+    dstc_emit(c, sm,
+            (defindex << 16) |
+            (localslot << 8) |
+            DOP_CLOSURE);
+    
+    if (ret.index != localslot) {
+        dstc_emit(c, sm, 
+                (ret.index << 16) |
+                (localslot << 8) |
+                DOP_MOVE_FAR);
+    }
+
+    return ret;
+}
+
+/* Keep in lexographic order */
+static const DstSpecial dstc_specials[] = {
+    {"def", dstc_def},
+    {"do", dstc_do},
+    {"fn", dstc_fn},
+    {"if", dstc_if},
+    {"quote", dstc_quote},
+    {"transfer", dstc_transfer},
+    {"var", dstc_var},
+    {"varset!", dstc_varset},
+    {"while", dstc_while}
+};
+
+/* Find a special */
+const DstSpecial *dstc_special(const uint8_t *name) {
+    return dst_strbinsearch(
+            &dstc_specials,
+            sizeof(dstc_specials)/sizeof(DstSpecial),
+            sizeof(DstSpecial),
+            name);
+}
+

core/fiber.c

@@ -45,7 +45,7 @@ DstFiber *dst_fiber_reset(DstFiber *fiber) {
     fiber->frame = 0;
     fiber->stackstart = DST_FRAME_SIZE;
     fiber->stacktop = DST_FRAME_SIZE;
-    fiber->status = DST_FIBER_DEAD;
+    fiber->status = DST_FIBER_PENDING;
     fiber->parent = NULL;
     return fiber;
 }

core/io.c

@@ -1,3 +1,26 @@
+/*
+* Copyright (c) 2017 Calvin Rose
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to
+* deal in the Software without restriction, including without limitation the
+* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+* sell copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+* IN THE SOFTWARE.
+*/
+
+#include <dst/dst.h>
 
 DstAbstractType dst_stl_filetype = {
     "stl.file",
@@ -6,27 +29,6 @@ DstAbstractType dst_stl_filetype = {
     NULL
 };
 
-/* Open a a file and return a userdata wrapper around the C file API. */
-int dst_stl_open(int32_t argn, Dst *argv, Dst *ret) {
-    if (argn < 2) {
-        *ret = dst_cstringv("expected at least 2 arguments");
-        return 1;
-    }
-    const uint8_t *fname = dst_to_string(argv[0]);
-    const uint8_t *fmode = dst_to_string(argv[1]);
-    FILE *f;
-    FILE **fp;
-    f = fopen((const char *)fname, (const char *)fmode);
-    if (!f) {
-        dst_c_throwc("could not open file");
-        return 1;
-    }
-    fp = dst_astract(sizeof(FILE *), &dst_stl_filetype);
-    *fp = f;
-    *ret = dst_wrap_abstract(fp);
-    return 0;
-}
-
 /* Check file argument */
 static FILE **checkfile(int32_t argn, Dst *argv, Dst *ret, int32_t n) {
     FILE **fp;
@@ -62,10 +64,44 @@ static DstBuffer *checkbuffer(int32_t argn, Dst *argv, Dst *ret, int32_t n, int
     return dst_unwrap_abstract(argv[n]);
 }
 
+/* Check char array argument */
+static int checkchars(int32_t argn, Dst *argv, Dst *ret, int32_t n, const uint8_t **str, int32_t *len) {
+    if (n >= argn) {
+        *ret = dst_cstringv("expected string/buffer");
+        return 0;
+    }
+    if (!dst_chararray_view(argv[n], str, len)) {
+        *ret = dst_cstringv("expected string/buffer");
+        return 0;
+    }
+    return 1;
+}
+
+/* Open a a file and return a userdata wrapper around the C file API. */
+int dst_stl_fileopen(int32_t argn, Dst *argv, Dst *ret) {
+    if (argn < 2) {
+        *ret = dst_cstringv("expected at least 2 arguments");
+        return 1;
+    }
+    const uint8_t *fname = dst_to_string(argv[0]);
+    const uint8_t *fmode = dst_to_string(argv[1]);
+    FILE *f;
+    FILE **fp;
+    f = fopen((const char *)fname, (const char *)fmode);
+    if (!f) {
+        *ret = dst_cstringv("could not open file");
+        return 1;
+    }
+    fp = dst_abstract(&dst_stl_filetype, sizeof(FILE *));
+    *fp = f;
+    *ret = dst_wrap_abstract(fp);
+    return 0;
+}
+
 /* Read an entire file into memory */
 int dst_stl_slurp(int32_t argn, Dst *argv, Dst *ret) {
     DstBuffer *b;
-    long fsize;
+    size_t fsize;
     FILE *f;
     FILE **fp = checkfile(argn, argv, ret, 0);
     if (!fp) return 1;
@@ -76,13 +112,15 @@ int dst_stl_slurp(int32_t argn, Dst *argv, Dst *ret) {
     fseek(f, 0, SEEK_END);
     fsize = ftell(f);
     fseek(f, 0, SEEK_SET);
-    if (fsize > INT32_MAX || fsize + b->count > INT32_MAX) {
+    if (fsize > INT32_MAX || dst_buffer_extra(b, fsize)) {
         *ret = dst_cstringv("buffer overflow");
         return 1;
     }
     /* Ensure buffer size */
-    dst_buffer_extra(b, fsize);
+    if (fsize != fread((char *)(b->data + b->count), fsize, 1, f)) {
-    fread((char *)(b->data + b->count), fsize, 1, f);
+        *ret = dst_cstringv("error reading file");
+        return 1;
+    }
     b->count += fsize;
     /* return */
     *ret = dst_wrap_buffer(b);
@@ -90,7 +128,7 @@ int dst_stl_slurp(int32_t argn, Dst *argv, Dst *ret) {
 }
 
 /* Read a certain number of bytes into memory */
-int dst_stl_read(Dst *vm) {
+int dst_stl_fileread(int32_t argn, Dst *argv, Dst *ret) {
     DstBuffer *b;
     FILE *f;
     int32_t len;
@@ -110,30 +148,53 @@ int dst_stl_read(Dst *vm) {
 
     f = *fp;
     /* Ensure buffer size */
-    if (len + bcount
+    if (dst_buffer_extra(b, len)) {
-    dst_buffer_extra(b, len);
+        *ret = dst_cstringv("buffer overflow");
+        return 1;
+    }
     b->count += fread((char *)(b->data + b->count), len, 1, f) * len;
     *ret = dst_wrap_buffer(b);
     return 0;
 }
 
 /* Write bytes to a file */
-int dst_stl_write(Dst *vm) {
+int dst_stl_filewrite(int32_t argn, Dst *argv, Dst *ret) {
     FILE *f;
-    const uint8_t *data;
+    int32_t len, i;
-    uint32_t len;
+    FILE **fp = checkfile(argn, argv, ret, 0);
-    FILE **fp = dst_check_userdata(vm, 0, &dst_stl_filetype);
+    const uint8_t *str;
-    if (fp == NULL) dst_c_throwc(vm, "expected file");
+    if (!fp) return 1;
-    if (!dst_chararray_view(dst_arg(vm, 1), &data, &len)) dst_c_throwc(vm, "expected string|buffer");
+    if (!dst_checktype(argv[1], DST_INTEGER)) {
+        *ret = dst_cstringv("expected positive integer");
+        return 1;
+    }
+    len = dst_unwrap_integer(argv[1]);
+    if (len < 0) {
+        *ret = dst_cstringv("expected positive integer");
+        return 1;
+    }
+    
+    for (i = 1; i < argn; i++) {
+        if (!checkchars(argn, argv, ret, i, &str, &len)) return 1;
+        
         f = *fp;
-    fwrite(data, len, 1, f);
+        if (len != (int32_t) fwrite(str, len, 1, f)) {
-    return DST_RETURN_OK;
+            *ret = dst_cstringv("error writing to file");
+            return 1;
+        }
+    }
+    return 0;
 }
 
 /* Close a file */
-int dst_stl_close(Dst *vm) {
+int dst_stl_fileclose(int32_t argn, Dst *argv, Dst *ret) {
-    FILE **fp = dst_check_userdata(vm, 0, &dst_stl_filetype);
+    FILE *f;
-    if (fp == NULL) dst_c_throwc(vm, "expected file");
+    FILE **fp = checkfile(argn, argv, ret, 0);
-    fclose(*fp);
+    if (!fp) return 1;
-    dst_c_return(vm, dst_wrap_nil());
+    f = *fp;
+    if (fclose(f)) {
+        *ret = dst_cstringv("could not close file");
+        return 1;
+    }
+    return 0;
 }

core/stl.c

@@ -55,6 +55,21 @@ int dst_stl_describe(int32_t argn, Dst *argv, Dst *ret) {
     return 0;
 }
 
+int dst_stl_string(int32_t argn, Dst *argv, Dst *ret) {
+    int32_t i;
+    DstBuffer b;
+    dst_buffer_init(&b, 0);
+    for (i = 0; i < argn; ++i) {
+        int32_t len;
+        const uint8_t *str = dst_to_string(argv[i]);
+        len = dst_string_length(str);
+        dst_buffer_push_bytes(&b, str, len);
+    }
+    *ret = dst_stringv(b.data, b.count);
+    dst_buffer_deinit(&b);
+    return 0;
+}
+
 int dst_stl_asm(int32_t argn, Dst *argv, Dst *ret) {
     DstAssembleOptions opts;
     DstAssembleResult res;
@@ -254,6 +269,7 @@ static DstReg stl[] = {
     {"real", dst_real},
     {"print", dst_stl_print},
     {"describe", dst_stl_describe},
+    {"string", dst_stl_string},
     {"table", dst_stl_table},
     {"array", dst_stl_array},
     {"tuple", dst_stl_tuple},
@@ -295,7 +311,11 @@ static DstReg stl[] = {
     {">>", dst_lshift},
     {"<<", dst_rshift},
     {">>>", dst_lshiftu},
-    {"not", dst_stl_not}
+    {"not", dst_stl_not},
+    {"fopen", dst_stl_fileopen},
+    {"fclose", dst_stl_fileclose},
+    {"fwrite", dst_stl_filewrite},
+    {"fread", dst_stl_fileread}
 };
 
 Dst dst_loadstl(int flags) {

dsttest/suite0.dst

@@ -112,21 +112,21 @@
 
 # Fiber tests
 
-(def athread (thread (fn [x]
+(def afiber (fiber (fn [x]
 	(error (string "hello, " x)))))
 
-(def athread-result (tran athread "world!"))
+(def afiber-result (transfer afiber "world!"))
 
-(assert (= athread-result "hello, world!") "thread error result")
+(assert (= afiber-result "hello, world!") "fiber error result")
-(assert (= (status athread) "error") "thread error status")
+(assert (= (status afiber) "error") "fiber error status")
 
 # yield tests
 
-(def t (thread (fn [] (tran nil 1) (tran nil 2) 3)))
+(def t (fiber (fn [] (transfer nil 1) (transfer nil 2) 3)))
 
-(assert (= 1 (tran t)) "initial transfer to new thread")
+(assert (= 1 (transfer t)) "initial transfer to new thread")
-(assert (= 2 (tran t)) "second transfer to thread")
+(assert (= 2 (transfer t)) "second transfer to thread")
-(assert (= 3 (tran t)) "return from thread")
+(assert (= 3 (transfer t)) "return from thread")
 (assert (= (status t) "dead") "finished thread is dead")
 
 # Var arg tests

include/dst/dst.h

@@ -151,6 +151,7 @@ int dst_hashtable_view(Dst tab, const DstKV **data, int32_t *len, int32_t *cap);
 #define dst_abstract_header(u) ((DstAbstractHeader *)(u) - 1)
 #define dst_abstract_type(u) (dst_abstract_header(u)->type)
 #define dst_abstract_size(u) (dst_abstract_header(u)->size)
+void *dst_abstract(const DstAbstractType *type, size_t size);
 
 /* Value functions */
 int dst_equals(Dst x, Dst y);

include/dst/dststl.h

@@ -68,4 +68,10 @@ int dst_lshift(int argn, Dst *argv, Dst *ret);
 int dst_rshift(int argn, Dst *argv, Dst *ret);
 int dst_lshiftu(int argn, Dst *argv, Dst *ret);
 
+int dst_stl_fileopen(int32_t argn, Dst *argv, Dst *ret);
+int dst_stl_slurp(int32_t argn, Dst *argv, Dst *ret);
+int dst_stl_fileread(int32_t argn, Dst *argv, Dst *ret);
+int dst_stl_filewrite(int32_t argn, Dst *argv, Dst *ret);
+int dst_stl_fileclose(int32_t argn, Dst *argv, Dst *ret);
+
 #endif /* DST_MATH_H_defined */