Update sourcemapping structure. Add seqs example file.

examples/lazyseqs.dst

@@ -0,0 +1,82 @@
+# An example implementation of functional, lazy
+# sequences, like in clojure.
+# Use with (import "./path/to/this/file" :prefix "seq/")
+
+(defn- mem0 [f]
+ "Memoize a 0 arity function."
+ (var state nil)
+ (var loaded nil)
+ (fn []
+  (if loaded
+   state
+   (do 
+    (def n (f))
+    (varset! state n)
+    (varset! loaded true)
+    n))))
+
+(defmacro delay 
+ "Macro for lazy evaluation"
+ [x] (tuple mem0 (tuple 'fn [] x)))
+
+# Use tuples instead of structs to save memory
+(def HEAD :private 0)
+(def TAIL :private 1)
+
+(defn empty-seq 
+ "The empty sequence." 
+ [] nil)
+
+(defn cons 
+ "Create a new sequence by prepending a value to the original sequence."
+ [h t]
+ (delay (tuple h t)))
+
+(defn empty? 
+ "Check if a sequence is empty."
+ [s]
+ (not (s)))
+
+(defn head
+ "Get the next value of the sequence."
+ [s]
+ (get (s) HEAD))
+
+(defn tail
+ "Get the rest of a sequence"
+ [s]
+ (get (s) TAIL))
+
+(defn range 
+ "Return a sequence of integers [start, end)."
+ [start end]
+ (if (< start end)
+  (cons start (range (+ 1 start) end))
+  empty-seq))
+
+(defn map
+ "Return a sequence that is the result of apply f to each value in s."
+ [f s]
+ (if (s) (cons (f (head s)) (map f (tail s))) empty-seq))
+
+(defn realize
+ "Force evaluation of a lazy sequence."
+ [s]
+ (when (s) (realize (tail s))))
+
+(defn realize-map [f s]
+ "Evaluate f on each member of the sequence. Forces evaluation."
+ (when (s) (f (head s)) (realize-map f (tail s))))
+
+(defn drop 
+ "Ignores the first n values of the sequence and returns the rest."
+ [n s]
+ (if (s) (if (zero? n) s (drop (- n 1) (tail s))) empty-seq))
+
+(defn take
+ "Returns at most the first n values of s."
+ [n s]
+ (if (and (s) (pos? n))
+  (cons (head s) (take (- n 1) (tail s)))
+  empty-seq))
+

src/assembler/asm.c

@@ -658,10 +658,11 @@ static DstAssembleResult dst_asm1(DstAssembler *parent, Dst source, int flags) {
     x = dst_get(s, dst_csymbolv("sourcemap"));
     if (dst_seq_view(x, &arr, &count)) {
         dst_asm_assert(&a, count == def->bytecode_length, "sourcemap must have the same length as the bytecode");
-        def->sourcemap = malloc(sizeof(int32_t) * 2 * count);
+        def->sourcemap = malloc(sizeof(DstSourceMapping) * count);
         for (i = 0; i < count; i++) {
             const Dst *tup;
             Dst entry = arr[i];
+            DstSourceMapping mapping;
             if (!dst_checktype(entry, DST_TUPLE)) {
                 dst_asm_error(&a, "expected tuple");
             }
@@ -672,8 +673,9 @@ static DstAssembleResult dst_asm1(DstAssembler *parent, Dst source, int flags) {
             if (!dst_checktype(tup[1], DST_INTEGER)) {
                 dst_asm_error(&a, "expected integer");
             }
-            def->sourcemap[2*i] = dst_unwrap_integer(tup[0]);
-            def->sourcemap[2*i+1] = dst_unwrap_integer(tup[1]);
+            mapping.start = dst_unwrap_integer(tup[0]);
+            mapping.end = dst_unwrap_integer(tup[1]);
+            def->sourcemap[i] = mapping;
         }
     }
 
@@ -831,11 +833,12 @@ Dst dst_disasm(DstFuncDef *def) {
     /* Add source map */
     if (NULL != def->sourcemap) {
         DstArray *sourcemap = dst_array(def->bytecode_length);
-        for (i = 0; i < def->bytecode_length * 2; i += 2) {
+        for (i = 0; i < def->bytecode_length; i++) {
             Dst *t = dst_tuple_begin(2);
-            t[0] = dst_wrap_integer(def->sourcemap[i]);
-            t[1] = dst_wrap_integer(def->sourcemap[i + 1]);
-            sourcemap->data[i / 2] = dst_wrap_tuple(dst_tuple_end(t));
+            DstSourceMapping mapping = def->sourcemap[i];
+            t[0] = dst_wrap_integer(mapping.start);
+            t[1] = dst_wrap_integer(mapping.end);
+            sourcemap->data[i] = dst_wrap_tuple(dst_tuple_end(t));
         }
         sourcemap->count = def->bytecode_length;
         dst_table_put(ret, dst_csymbolv("sourcemap"), dst_wrap_array(sourcemap));

src/compiler/boot.dst

@@ -1,3 +1,5 @@
+# Bootstrap the dst environment
+# Copyright 2018 (C) Calvin Rose
 
 # Capture the current env
 (var *env*
@@ -26,6 +28,12 @@
    (def args (array-concat [] name :macro more))
    (apply defn* args))))
 
+(defmacro defmacro-
+ "Define a private macro that will not be exported."
+ [name & more]
+ (apply tuple (array-concat
+  ['defmacro name :private] more)))
+
 (defmacro defn-
  "Define a private function that will not be exported."
  [name & more]
@@ -36,6 +44,8 @@
 (defn odd? [x] (== 1 (% x 2)))
 (defn nil? [x] (= x nil))
 (defn zero? [x] (== x 0))
+(defn pos? [x] (> x 0))
+(defn neg? [x] (< x 0))
 (defn one? [x] (== x 1))
 (defn inc [x] (+ x 1))
 (defn dec [x] (- x 1))

src/compiler/compile.c

@@ -903,20 +903,22 @@ DstFuncDef *dstc_pop_funcdef(DstCompiler *c) {
         dst_v__cnt(c->buffer) = scope.bytecode_start;
         if (NULL != c->mapbuffer) {
             int32_t i;
-            size_t s = sizeof(int32_t) * 2 * dst_v_count(c->mapbuffer);
-            def->sourcemap = malloc(2 * s);
+            size_t s = sizeof(DstSourceMapping) * dst_v_count(c->mapbuffer);
+            def->sourcemap = malloc(s);
             if (NULL == def->sourcemap) {
                 DST_OUT_OF_MEMORY;
             }
             for (i = 0; i < dst_v_count(c->mapbuffer); i++) {
                 DstAst *a = c->mapbuffer[i];
+                DstSourceMapping mapping;
                 if (a) {
-                    def->sourcemap[2 * i] = a->source_start;
-                    def->sourcemap[2 * i + 1] = a->source_end;
+                    mapping.start = a->source_start;
+                    mapping.end = a->source_end;
                 } else {
-                    def->sourcemap[2 * i] = -1;
-                    def->sourcemap[2 * i + 1] = -1;
+                    mapping.start = -1;
+                    mapping.end = -1;
                 }
+                def->sourcemap[i] = mapping;
             }
             dst_v__cnt(c->mapbuffer) = scope.bytecode_start;
         }

src/include/dst/dsttypes.h

@@ -52,6 +52,7 @@ typedef struct DstAbstractType DstAbstractType;
 typedef struct DstArgs DstArgs;
 typedef struct DstAst DstAst;
 typedef struct DstReg DstReg;
+typedef struct DstSourceMapping DstSourceMapping;
 typedef int (*DstCFunction)(DstArgs args);
 
 /* Basic types for all Dst Values */
@@ -378,6 +379,11 @@ struct DstKV {
 #define DST_FUNCDEF_FLAG_VARARG 1
 #define DST_FUNCDEF_FLAG_NEEDSENV 4
 
+struct DstSourceMapping {
+    int32_t start;
+    int32_t end;
+};
+
 /* A function definition. Contains information needed to instantiate closures. */
 struct DstFuncDef {
     int32_t *environments; /* Which environments to capture from parent. */
@@ -386,7 +392,7 @@ struct DstFuncDef {
     uint32_t *bytecode;
 
     /* Various debug information */
-    int32_t *sourcemap;
+    DstSourceMapping *sourcemap;
     const uint8_t *source;
     const uint8_t *sourcepath;