Add beginning of intorductory doc. Add prototypes to pretty print

output.

doc/intro.md

@@ -0,0 +1,159 @@
+# Dst Language Introduction
+
+Dst is a dynamic, lightweight programming language with strong functional
+capabilities as well as support for imperative programming. It to be used
+for short lived scripts as well as for building real programs. It can also
+be extended with native code (C modules) for better performance and interfacing with
+existing software. Dst takes ideas from Lua, Scheme, Clojure, Smalltalk, and 
+a whole bunch of other dynamic languages.
+
+# Hello, world!
+
+Following tradition, a simple Dst program will simply print "Hello, world!".
+
+```
+(print "Hello, world!")
+```
+
+Put the following code in a file call `hello.dst`, and run `./dst hello.dst`.
+The words "Hello, world!" should be printed to the console, and then the program
+should immediately exit. You now have a working dst program!
+
+Alternatively, run the program `./dst` without any arguments to enter a REPL,
+or read eval print loop. This is a mode where Dst functions like a calculator,
+reading some input from stdin, evaluating it, and printing out the result, all
+in an inifinte loop. This is a useful mode for exploring or prototyping in Dst.
+
+This is about the simplest program one can write, and consists of precisely
+three elements. This first element is the `print` symbol. This is a function
+that simply prints its arguments to standard out. The second argument is the
+string literal "Hello, world!", which is the one and only argument to the
+print function. Lastly, the print symbol and the string literal are wrapped
+in parentheses, forming a tuple. In Dst, parentheses and brackets are interchangeable,
+brackets are used mostly when the resulting tuple is not a function call. The tuple
+above indicates that the function `print` is to be called with one argument, `"Hello, world"`.
+
+Like all lisps, all operations in Dst are in prefix notation; the name of the
+operator is the first value in the tuple, and the arguments passed to it are
+in the rest of the tuple.
+
+# A bit more - Arithmetic
+
+Any programming language will have some way to do arithmetic. 
+
+```
+# Prints 13
+# (1 + (2*2) + (10/5) + 3 + 4 + (5 - 6))
+(print (+ 1 (* 2 2) (/ 10 5) 3 4 (- 5 6)))
+```
+
+Just like the print function, all arithmetic operators are entered in
+prefix notation. Dst also supports the modulo operator, or `%`, which returns
+the remainder of integer division. For example, `(% 10 3)` is 1, and `(% 10.5 3)` is
+1.5. The lines that begin with `#` are comments.
+
+Dst actually has to flavors of numbers; integers and real numbers. Integers are any
+integer value between -2,147,483,648 and 2,147,483,647 (32 bit signed integer). 
+Reals are real numbers, and are represented by IEEE-754 double precision floating point
+numbers. That means that they can represent any number an integer can represent, as well
+fractions to very high precision.
+
+Although real numbers can represent any value an integer can, try to distinguish between
+real numbers and integers in your program. If you are using a number to index into a structure,
+you probably want integers. Otherwise, you may want to use reals (this is only a rule of thumb).
+
+Arithmetic operator will convert integers to real numbers if needed, but real numbers
+will not be converted to integers, as not all real numbers can be safely convert to integers.
+
+## Numeric literals
+
+Numeric literals can be written in many ways. Numbers can be written in base 10, with
+underscores used to separate digits into groups. A decimal point can be used for floating
+point numbers. Numbers can also be written in other bases by prefixing the number with the desired
+base and the character 'r'. For example, 16 can be written as `16`, `1_6`, `16r10`, `4r100`, or `0x10`. The
+`0x` prefix can be used for hexadecimal as it is so common. The radix must be themselves written in base 10, and
+can be any integer from 2 to 36. For any radix above 10, use the letters as digits (not case sensitive).
+
+Numbers can also be in scientific notation such as `3e10`. A custom radix can be used as well
+as for scientific notation numbers, (the exponent will share the radix). For numbers in scientific
+notation with a radix besides 10, use the `&` symbol to indicate the exponent rather then `e`.
+
+# Functions
+
+Dst is a functional language - that means that one of the basic building blocks of your
+program will be defining functions (the other is using data structures). Because dst
+is a Lisp, functions are values just like numbers or strings - they can be passed around and
+created as needed.
+
+Functions can be defined with the `defn` macro, like so:
+
+```
+(defn triangle-area [base height]
+ (print "calculating area of a triangle...")
+ (* base height 0.5))
+```
+
+A function defined with `defn` has a number of parts. First, it has it's name, triangle-area. This
+is just a symbol used to access the function later. Next is the list of parameters this function takes,
+in this case two parameters named base and height. Lastly, a function made with defn has
+a number of body statements, which get executed each time the function is called. The last
+form in the body is what the function evaluates to, or returns.
+
+Once a function like the above one is defined, the programmer can use the `triangle-area`
+function just like any other, say `print` or `+`.
+
+```
+# Prints "calculating area of a triangle..." and then "25"
+(print (triangle-area 5 10))
+```
+
+Note that when nesting function calls in other function calls like above (a call to triangle-area is
+nested inside a call to print), the inner function calls are evaluated first. Also, arguments to
+a function call are evaluated in order, from first argument to last argument).
+
+Because functions are first-class values like numbers or strings, they can be passed
+as arguments to other functions as well
+
+```
+(print triangle-area)
+```
+
+Prints the location in memory of the function triangle area. This idea can be used
+to build some powerful constructs purely out of functions, or closures as they are known
+in many contexts.
+
+Functions don't need to have names. The `fn` keyword can be used to introduce function
+literals without binding them to a symbol.
+
+```
+# Evaluates to 40
+((fn [x y] (+ x x y)) 10 20)
+```
+
+The above expression first creates an anonymous function that adds twice
+the first argument to the second, and then calls that function with arguments 10 and 20.
+This will return (10 + 10 + 20) = 40.
+
+# Defs and Vars
+
+Values can be bound to symbols for later use using the keyword `def`. Using undefined
+symbols will raise an error.
+
+```
+(def a 100)
+(def b (+ 1 a))
+(def c (+ b b))
+(def d (- c 100))
+```
+
+Bindings created with def have lexical scoping. Also, bindings created with def are immutable; they
+cannot be changed after definition. For mutable bindings, like variables in other programming
+languages, use the `var` keyword. The assignment special form `:=` can then be used to update
+a var.
+
+```
+(var myvar 1)
+(print myvar)
+(:= myvar 10)
+(print myvar)
+```

src/compiler/boot.dst

@@ -675,7 +675,7 @@ to call on any table. Does not print table prototype information."
       (buffer-popn indent 2)
       (buffer-push-string buf indent))))
 
-  (defn pp-dict-nested [y]
+  (defn pp-dict-nested [y proto?]
    (buffer-push-string indent "  ")
    (def ps (sort (pairs y)))
    (for [i 0 (length ps)]
@@ -684,6 +684,10 @@ to call on any table. Does not print table prototype information."
     (recur k)
     (buffer-push-string buf " ")
     (recur v))
+   (when proto?
+    (buffer-push-string buf indent)
+    (buffer-push-string buf "{proto} ")
+    (recur proto?))
    (buffer-popn indent 2)
    (buffer-push-string buf indent))
 
@@ -697,7 +701,9 @@ to call on any table. Does not print table prototype information."
     (recur v)))
 
   (defn pp-dict [y]
-   ((if (> 4 (length y)) pp-dict-simple pp-dict-nested) y))
+   (def proto? (and (table? y) (getproto y)))
+   (def complex? (or proto? (> (length y) 4)))
+   ((if complex? pp-dict-nested pp-dict-simple) y proto?))
 
   (def printers {
    :array  (fn [y] (do-ds y "@[" "]" true pp-seq))

src/core/state.h

@@ -32,7 +32,10 @@ extern "C" {
 #include <dst/dsttypes.h>
 
 /* The VM state. Rather than a struct that is passed
- * around, the vm state is global for simplicity. */
+ * around, the vm state is global for simplicity. If 
+ * at some point a a global state object, or contenxt,
+ * is required to be passed around, this is waht would
+ * be in it. */
 
 /* How many VM stacks have been entered */
 extern DST_THREAD_LOCAL int dst_vm_stackn;

src/core/table.c

@@ -237,10 +237,8 @@ void dst_table_merge_struct(DstTable *table, const DstKV *other) {
 
 static int cfun_tostruct(DstArgs args) {
     DstTable *t;
-    if (args.n != 1 || !dst_checktype(args.v[0], DST_TABLE)) {
+    dst_fixarity(args, 1);
-        return dst_throw(args, "expected table");
+    dst_arg_table(t, args, 0);
-    }
-    t = dst_unwrap_table(args.v[0]);
     return dst_return(args, dst_wrap_struct(dst_table_to_struct(t)));
 }
 

src/include/dst/dst.h

@@ -235,19 +235,6 @@ int dst_typeabstract_err(DstArgs args, int32_t n, DstAbstractType *at);
     }\
 } while (0)
 
-#define dst_arg_abstract(DEST, A, N, AT) do {\
-    dst_checkabstract(A, N, AT);\
-    DEST = dst_unwrap_abstract((A).v[(N)]);\
-} while (0)
-
-#define dst_arg_integer(DEST, A, N) do { \
-    dst_check(A, N, DST_INTEGER);\
-    DEST = dst_unwrap_integer((A).v[(N)]); } while (0)
-
-#define dst_arg_real(DEST, A, N) do { \
-    dst_check(A, N, DST_REAL);\
-    DEST = dst_unwrap_real((A).v[(N)]); } while (0)
-
 #define dst_arg_number(DEST, A, N) do { \
     if ((A).n <= (N)) return dst_typemany_err(A, N, DST_TFLAG_NUMBER);\
     Dst val = (A).v[(N)];\
@@ -259,17 +246,24 @@ int dst_typeabstract_err(DstArgs args, int32_t n, DstAbstractType *at);
     dst_checkmany(A, N, DST_TFLAG_TRUE | DST_TFLAG_FALSE);\
     DEST = dst_unwrap_boolean((A).v[(N)]); } while (0)
 
-#define dst_arg_string(DEST, A, N) do { \
+#define _dst_arg(TYPE, NAME, DEST, A, N) do { \
-    dst_check(A, N, DST_STRING);\
+    dst_check(A, N, TYPE);\
-    DEST = dst_unwrap_string((A).v[(N)]); } while (0)
+    DEST = dst_unwrap_##NAME((A).v[(N)]); } while (0)
 
-#define dst_arg_symbol(DEST, A, N) do { \
+#define dst_arg_fiber(DEST, A, N) _dst_arg(DST_FIBER, fiber, DEST, A, N)
-    dst_check(A, N, DST_SYMBOL);\
+#define dst_arg_integer(DEST, A, N) _dst_arg(DST_INTEGER, integer, DEST, A, N)
-    DEST = dst_unwrap_string((A).v[(N)]); } while (0)
+#define dst_arg_real(DEST, A, N) _dst_arg(DST_REAL, real, DEST, A, N)
+#define dst_arg_string(DEST, A, N) _dst_arg(DST_STRING, string, DEST, A, N)
+#define dst_arg_symbol(DEST, A, N) _dst_arg(DST_SYMBOL, symbol, DEST, A, N)
+#define dst_arg_array(DEST, A, N) _dst_arg(DST_ARRAY, array, DEST, A, N)
+#define dst_arg_tuple(DEST, A, N) _dst_arg(DST_TUPLE, tuple, DEST, A, N)
+#define dst_arg_table(DEST, A, N) _dst_arg(DST_TABLE, table, DEST, A, N)
+#define dst_arg_struct(DEST, A, N) _dst_arg(DST_STRUCT, st, DEST, A, N)
+#define dst_arg_buffer(DEST, A, N) _dst_arg(DST_BUFFER, buffer, DEST, A, N)
+#define dst_arg_function(DEST, A, N) _dst_arg(DST_FUNCTION, function, DEST, A, N)
+#define dst_arg_cfunction(DEST, A, N) _dst_arg(DST_CFUNCTION, cfunction, DEST, A, N)
 
-#define dst_arg_buffer(DEST, A, N) do { \
+#define dst_arg_abstract(DEST, A, N) _dst_arg(DST_ABSTRACT, abstract, DEST, A, N)
-    dst_check(A, N, DST_BUFFER);\
-    DEST = dst_unwrap_buffer((A).v[(N)]); } while (0)
 
 #ifdef __cplusplus
 }