Things are in motion.

Moves all print functions to own file for sanity.

Also, just hit 2,000 lines; nice.

TODO.md

@@ -1,7 +1,7 @@
-0. Create file to describe properties of terminology used; param, arg, var, &c.
+1. Differentiate parameters and arguments -- params for function definitions,
-1. Differenciate parameters and arguments -- params for function definitions,
 arguments for function calls
-2. Add scope field to all ASTs, and new scope layer for those that need it.
 
 Change editor to GNU Readline.
 Make variables persist through lines in the editor.
+
+Return syntax errors as exceptions.

definitions.md

@@ -0,0 +1,36 @@
+Lambda
+    size_t parmc
+    AST** parmv
+    AST* body
+
+Call
+    Lambda to
+        size_t parmc
+        AST** parmv
+    size_t argc
+    AST** argv
+
+VDef
+    char* name
+    AST* exp
+
+(\(x) x * 2)(4)
+
+Call
+to:
+    Lambda
+    parc: 1
+    parv: [ x ]
+    body: 
+        Call
+        to:
+            BIF(mul)
+         argc: 2
+         argv: [
+             VRef
+             name: x
+
+             2
+         ]
+argc: 1
+argv: [ 4 ]

examples/function.scl

@@ -1,3 +1,3 @@
-f(n) 2 * n
+f(n) = 2 * n
 
 f(5)

src/ast.c

@@ -2,24 +2,12 @@
 #include <stdio.h>
 
 #include "include/ast.h"
-#include "include/dstr.h"
 #include "include/gc.h"
 #include "include/scope.h"
 #include "include/util.h"
 
 extern AST* root;
 
-static char* asttype_names[] = {
-    [AST_TYPE_CALL] = "FUNC CALL",
-    [AST_TYPE_NUM] = "NUMBER",
-    [AST_TYPE_VREF] = "VAR REFERENCE",
-    [AST_TYPE_VDEF] = "VAR DEFINITION",
-    [AST_TYPE_BLOCK] = "BLOCK",
-    [AST_TYPE_EXC] = "EXCEPTION",
-    [AST_TYPE_FDEF] = "FUNCTION DEFINITION",
-    [AST_TYPE_ARG] = "DEFINITION ARGUMENT"
-};
-
 AST* ast_init(ASTType type, void* data) {
     AST* ast = gc_alloc(sizeof(AST), GC_TYPE_AST);
 
@@ -51,36 +39,16 @@ void ast_destroy(AST* ast) {
     if (!ast) return;
 
     switch (ast->type) {
-        case AST_TYPE_NUM:   ast_num_data_destroy(ast->data); break;
+        case AST_TYPE_NUM:    ast_num_data_destroy(ast->data); break;
-        case AST_TYPE_CALL:  ast_call_data_destroy(ast->data); break;
+        case AST_TYPE_CALL:   ast_call_data_destroy(ast->data); break;
-        case AST_TYPE_VREF:  ast_vref_data_destroy(ast->data); break;
+        case AST_TYPE_VREF:   ast_vref_data_destroy(ast->data); break;
-        case AST_TYPE_VDEF:  ast_vdef_data_destroy(ast->data); break;
+        case AST_TYPE_VDEF:   ast_vdef_data_destroy(ast->data); break;
-        case AST_TYPE_BLOCK: ast_block_data_destroy(ast->data); break;
+        case AST_TYPE_BLOCK:  ast_block_data_destroy_psv(ast->data); break;
-        case AST_TYPE_FDEF:  ast_fdef_data_destroy(ast->data); break;
+        case AST_TYPE_FDEF:   ast_fdef_data_destroy_psv(ast->data); break;
-        case AST_TYPE_ARG:   ast_arg_data_destroy(ast->data); break;
+        case AST_TYPE_ARG:    ast_arg_data_destroy(ast->data); break;
-        default:
+        case AST_TYPE_BIF:    ast_bif_data_destroy(ast->data); break;
-            log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
+        case AST_TYPE_EXC:    ast_exc_data_destroy(ast->data); break;
-    }
+        case AST_TYPE_LAMBDA: ast_lambda_data_destroy(ast->data); break;
-
-    // If there're no more `AST`s linked to the scope, free.
-    if (ast->scope && !--ast->scope->uses) scope_destroy_psv(ast->scope);
-
-    free(ast);
-}
-
-void ast_destroy_psv(AST* ast) {
-    if (!ast) return;
-
-    switch (ast->type) {
-        case AST_TYPE_NUM:   ast_num_data_destroy(ast->data); break;
-        case AST_TYPE_CALL:  ast_call_data_destroy_psv(ast->data); break;
-        case AST_TYPE_VREF:  ast_vref_data_destroy(ast->data); break;
-        case AST_TYPE_VDEF:  ast_vdef_data_destroy_psv(ast->data); break;
-        case AST_TYPE_BLOCK: ast_block_data_destroy_psv(ast->data); break;
-        case AST_TYPE_FDEF:  ast_fdef_data_destroy_psv(ast->data); break;
-        case AST_TYPE_ARG:   ast_arg_data_destroy(ast->data); break;
-        case AST_TYPE_BIF:   ast_bif_data_destroy(ast->data); break;
-        case AST_TYPE_EXC:   ast_exc_data_destroy(ast->data); break;
         default:
             log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
     }
@@ -88,35 +56,6 @@ void ast_destroy_psv(AST* ast) {
     free(ast);
 }
 
-void ast_print(AST* ast) {
-    if (!ast) return;
-    ast_print_i(ast, 0);
-}
-
-void ast_print_i(AST* ast, int i) {
-    INDENT_BEGIN(i);
-
-    INDENT_TITLE("AST", ast);
-    INDENT_FIELD("type", "%s", asttype_names[ast->type]);
-    INDENT_FIELD("scope", "%p", ast->scope);
-    INDENT_FIELD_EXT_NONL_START("data");
-    switch (ast->type) {
-        case AST_TYPE_NUM:
-            printf("%s  %lf\n", INDENT_spacing->buf, *(ASTNumData*)ast->data);
-            break;
-        case AST_TYPE_CALL:  ast_call_print(ast->data, i + 2); break;
-        case AST_TYPE_EXC:   ast_exc_print(ast->data, i + 2); break;
-        case AST_TYPE_VREF:  ast_vref_print(ast->data, i + 2); break;
-        case AST_TYPE_VDEF:  ast_vdef_print(ast->data, i + 2); break;
-        case AST_TYPE_BLOCK: ast_block_print(ast->data, i + 2); break;
-        case AST_TYPE_FDEF:  ast_fdef_print(ast->data, i + 2); break;
-        case AST_TYPE_ARG:   ast_arg_print(ast->data, i + 2); break;
-        default:             exit(1);
-    }
-    INDENT_FIELD_NONL_END;
-    INDENT_END;
-}
-
 ASTNumData* ast_num_data_init(double val) {
     talloc(ASTNumData, num);
 
@@ -127,14 +66,6 @@ ASTNumData* ast_num_data_init(double val) {
 
 void ast_num_data_destroy(ASTNumData* num) { free(num); }
 
-void ast_num_print(ASTNumData* data, int i) {
-    INDENT_BEGIN(i);
-
-    INDENT_FIELD("data", "%lf", *data);
-
-    INDENT_END;
-}
-
 ASTExcData* ast_exc_data_init(const char* msg, AST* trace) {
     ASTExcData* data = malloc(sizeof(ASTExcData));
     data->msg = msg;
@@ -147,31 +78,33 @@ void ast_exc_data_destroy(ASTExcData* exc) {
     free(exc);
 }
 
-void ast_exc_print(ASTExcData* data, int i) {
-    INDENT_BEGIN(i);
-
-    INDENT_TITLE("ASTExcData", data);
-    INDENT_FIELD("msg", "\"%s\"", data->msg);
-    if (data->trace == NULL) {
-        INDENT_FIELD("trace", "%p", NULL)
-    } else {
-        INDENT_FIELD_EXT_NONL_START("trace");
-        ast_print_i(data->trace, i + 1);
-        INDENT_FIELD_NONL_END;
-    }
-    INDENT_END;
-}
-
 ASTBIFData* ast_bif_data_init(AST* fn(size_t, AST**, Scope*)) {
     return (ASTBIFData*)fn;
 }
 
 void ast_bif_data_destroy(ASTBIFData* bif) { return; }
 
-ASTCallData* ast_call_data_init(char* to, size_t argc, AST** argv) {
+// Lambda.
-    talloc(ASTCallData, call);
 
-    log_dbgf("to: %s", to);
+ASTLambdaData* ast_lambda_data_init(size_t parc, AST** parv, AST* body) {
+    talloc(ASTLambdaData, lambda);
+
+    lambda->parc = parc;
+    lambda->parv = parv;
+    lambda->body = body;
+
+    return lambda;
+}
+
+void ast_lambda_data_destroy(ASTLambdaData* lambda) {
+    free(lambda->parv);
+    free(lambda);
+}
+
+// Call.
+
+ASTCallData* ast_call_data_init(size_t argc, AST** argv, AST* to) {
+    talloc(ASTCallData, call);
 
     call->to = to;
     call->argc = argc;
@@ -182,63 +115,27 @@ ASTCallData* ast_call_data_init(char* to, size_t argc, AST** argv) {
 
 void ast_call_data_destroy(ASTCallData* call) {
     if (!call) return;
-    free(call->to);
-    for (size_t i = 0; i < call->argc; i++) ast_destroy(call->argv[i]);
     free(call->argv);
     free(call);
 }
 
-void ast_call_data_destroy_psv(ASTCallData* call) {
+// VDef.
-    if (!call) return;
-    free(call->to);
-    call->to = NULL;
-    free(call->argv);
-    call->argv = NULL;
-    free(call);
-}
 
-void ast_call_print(ASTCallData* data, int i) {
+ASTVDefData* ast_vdef_data_init(char* name, AST* exp) {
-    INDENT_BEGIN(i);
-
-    INDENT_TITLE("ASTCallData", data);
-    INDENT_FIELD("to", "%s", data->to);
-    INDENT_FIELD("argc", "%ld", data->argc);
-    INDENT_FIELD_LIST("argv", data->argv, data->argc, ast_print_i);
-
-    INDENT_END;
-}
-
-ASTVDefData* ast_vdef_data_init(char* name, AST* val) {
     talloc(ASTVDefData, vdef);
 
     vdef->name = name;
-    vdef->val = val;
+    vdef->exp = exp;
 
     return vdef;
 }
 
 void ast_vdef_data_destroy(ASTVDefData* vdef) {
-    ast_destroy(vdef->val);
     free(vdef->name);
     free(vdef);
 }
 
-void ast_vdef_data_destroy_psv(ASTVDefData* vdef) {
+// VRef.
-    free(vdef->name);
-    free(vdef);
-}
-
-void ast_vdef_print(ASTVDefData* vdef, int depth) {
-    INDENT_BEGIN(depth);
-
-    INDENT_TITLE("ASTVDefData", vdef);
-    INDENT_FIELD("name", "%s", vdef->name);
-    INDENT_FIELD_EXT_NONL_START("val");
-    ast_print_i(vdef->val, depth + 2); // 2 because already indented.
-    INDENT_FIELD_NONL_END;
-
-    INDENT_END;
-}
 
 ASTVrefData* ast_vref_data_init(char* to) {
     talloc(ASTVrefData, vref);
@@ -253,15 +150,6 @@ void ast_vref_data_destroy(ASTVrefData* vref) {
     free(vref);
 }
 
-void ast_vref_print(ASTVrefData* data, int i) {
-    INDENT_BEGIN(i);
-
-    INDENT_TITLE("ASTVrefData", data);
-    INDENT_FIELD("to", "%s", data->to);
-
-    INDENT_END;
-}
-
 ASTBlockData* ast_block_data_init(AST** inside, size_t ln) {
     ASTBlockData* block = malloc(sizeof(ASTBlockData));
 
@@ -283,16 +171,6 @@ void ast_block_data_destroy_psv(ASTBlockData* block) {
     free(block);
 }
 
-void ast_block_print(ASTBlockData* data, int depth) {
-    INDENT_BEGIN(depth);
-
-    INDENT_TITLE("ASTBlockData", data);
-    INDENT_FIELD("ln", "%ld", data->ln);
-    INDENT_FIELD_LIST("inside", data->inside, data->ln, ast_print_i);
-
-    INDENT_END;
-}
-
 ASTFDefData*
 ast_fdef_data_init(char* name, size_t argc, AST** argv, AST* body) {
     ASTFDefData* fdef = malloc(sizeof(ASTFDefData));
@@ -317,18 +195,6 @@ void ast_fdef_data_destroy_psv(ASTFDefData* fdef) {
     free(fdef);
 }
 
-void ast_fdef_print(ASTFDefData* fdef, int i) {
-    INDENT_BEGIN(i)
-    INDENT_TITLE("ASTFDefData", fdef);
-    INDENT_FIELD("name", "%s", fdef->name);
-    INDENT_FIELD("argc", "%ld", fdef->argc);
-    INDENT_FIELD_LIST("argv", fdef->argv, fdef->argc, ast_print_i);
-    INDENT_FIELD_EXT_NONL_START("body");
-    ast_print_i(fdef->body, i + 2);
-    INDENT_FIELD_NONL_END;
-    INDENT_END;
-}
-
 ASTArgData* ast_arg_data_init(char* name) {
     ASTArgData* arg = malloc(sizeof(ASTArgData));
     arg->name = name;
@@ -337,13 +203,6 @@ ASTArgData* ast_arg_data_init(char* name) {
 
 void ast_arg_data_destroy(ASTArgData* arg) { free(arg->name); }
 
-void ast_arg_print(ASTArgData* arg, int i) {
-    INDENT_BEGIN(i);
-    INDENT_TITLE("ASTArgData", arg);
-    INDENT_FIELD("name", "%s", arg->name);
-    INDENT_END;
-}
-
 AST* ast_find(Scope* scope, char* name) {
     while (scope) {
         AST* gotten = htab_get(scope->here, name);

src/ast_print.c

@@ -0,0 +1,139 @@
+#include "include/ast_print.h"
+#include "include/dstr.h"
+#include "include/util.h"
+#include <stdio.h>
+
+static char* asttype_names[] = {
+    [AST_TYPE_CALL] = "FUNC CALL",
+    [AST_TYPE_NUM] = "NUMBER",
+    [AST_TYPE_VREF] = "VAR REFERENCE",
+    [AST_TYPE_VDEF] = "VAR DEFINITION",
+    [AST_TYPE_BLOCK] = "BLOCK",
+    [AST_TYPE_EXC] = "EXCEPTION",
+    [AST_TYPE_FDEF] = "FUNCTION DEFINITION",
+    [AST_TYPE_ARG] = "DEFINITION ARGUMENT",
+    [AST_TYPE_LAMBDA] = "LAMBDA EXPRESSION"
+};
+
+void ast_print(AST* ast) {
+    if (!ast) return;
+    ast_print_i(ast, 0);
+}
+
+void ast_print_i(AST* ast, int i) {
+    INDENT_BEGIN(i);
+
+    INDENT_TITLE("AST", ast);
+    INDENT_FIELD("type", "%s", asttype_names[ast->type]);
+    // INDENT_FIELD("scope", "%p", ast->scope);
+    INDENT_FIELD_EXT_NONL_START("data");
+    switch (ast->type) {
+        case AST_TYPE_NUM:
+            printf("%s  %lf\n", INDENT_spacing->buf, *(ASTNumData*)ast->data);
+            break;
+        case AST_TYPE_CALL:   ast_call_print(ast->data, i + 2); break;
+        case AST_TYPE_EXC:    ast_exc_print(ast->data, i + 2); break;
+        case AST_TYPE_VREF:   ast_vref_print(ast->data, i + 2); break;
+        case AST_TYPE_VDEF:   ast_vdef_print(ast->data, i + 2); break;
+        case AST_TYPE_BLOCK:  ast_block_print(ast->data, i + 2); break;
+        case AST_TYPE_FDEF:   ast_fdef_print(ast->data, i + 2); break;
+        case AST_TYPE_ARG:    ast_arg_print(ast->data, i + 2); break;
+        case AST_TYPE_LAMBDA: ast_lambda_print(ast->data, i + 2); break;
+        default:              exit(1);
+    }
+    INDENT_FIELD_NONL_END;
+    INDENT_END;
+}
+
+void ast_num_print(ASTNumData* data, int i) {
+    INDENT_BEGIN(i);
+
+    INDENT_FIELD("data", "%lf", *data);
+
+    INDENT_END;
+}
+
+void ast_exc_print(ASTExcData* data, int i) {
+    INDENT_BEGIN(i);
+
+    INDENT_TITLE("ASTExcData", data);
+    INDENT_FIELD("msg", "\"%s\"", data->msg);
+    if (data->trace == NULL) {
+        INDENT_FIELD("trace", "%p", NULL)
+    } else {
+        INDENT_FIELD_EXT_NONL_START("trace");
+        ast_print_i(data->trace, i + 1);
+        INDENT_FIELD_NONL_END;
+    }
+    INDENT_END;
+}
+
+void ast_call_print(ASTCallData* data, int i) {
+    INDENT_BEGIN(i);
+
+    INDENT_TITLE("ASTCallData", data);
+    INDENT_FIELD("to", "%s", data->to);
+    INDENT_FIELD("argc", "%ld", data->argc);
+    INDENT_FIELD_LIST("argv", data->argv, data->argc, ast_print_i);
+
+    INDENT_END;
+}
+void ast_vdef_print(ASTVDefData* vdef, int depth) {
+    INDENT_BEGIN(depth);
+
+    INDENT_TITLE("ASTVDefData", vdef);
+    INDENT_FIELD("name", "%s", vdef->name);
+    INDENT_FIELD_EXT_NONL_START("val");
+    ast_print_i(vdef->val, depth + 2); // 2 because already indented.
+    INDENT_FIELD_NONL_END;
+
+    INDENT_END;
+}
+
+void ast_vref_print(ASTVrefData* data, int i) {
+    INDENT_BEGIN(i);
+
+    INDENT_TITLE("ASTVrefData", data);
+    INDENT_FIELD("to", "%s", data->to);
+
+    INDENT_END;
+}
+
+void ast_block_print(ASTBlockData* data, int depth) {
+    INDENT_BEGIN(depth);
+
+    INDENT_TITLE("ASTBlockData", data);
+    INDENT_FIELD("ln", "%ld", data->ln);
+    INDENT_FIELD_LIST("inside", data->inside, data->ln, ast_print_i);
+
+    INDENT_END;
+}
+
+void ast_fdef_print(ASTFDefData* fdef, int i) {
+    INDENT_BEGIN(i)
+    INDENT_TITLE("ASTFDefData", fdef);
+    INDENT_FIELD("name", "%s", fdef->name);
+    INDENT_FIELD("argc", "%ld", fdef->argc);
+    INDENT_FIELD_LIST("argv", fdef->argv, fdef->argc, ast_print_i);
+    INDENT_FIELD_EXT_NONL_START("body");
+    ast_print_i(fdef->body, i + 2);
+    INDENT_FIELD_NONL_END;
+    INDENT_END;
+}
+void ast_arg_print(ASTArgData* arg, int i) {
+    INDENT_BEGIN(i);
+    INDENT_TITLE("ASTArgData", arg);
+    INDENT_FIELD("name", "%s", arg->name);
+    INDENT_END;
+}
+
+void ast_lambda_print(ASTLambdaData* lambda, int i) {
+    INDENT_BEGIN(i)
+    INDENT_TITLE("ASTLambdaData", lambda);
+    INDENT_FIELD("argc", "%ld", lambda->argc);
+    INDENT_FIELD_LIST("argv", lambda->argv, lambda->argc, ast_print_i);
+    INDENT_FIELD_EXT_NONL_START("body");
+    ast_print_i(lambda->body, i + 2);
+    INDENT_FIELD_NONL_END;
+    INDENT_END;
+}

src/exec.c

@@ -4,7 +4,6 @@
 
 #include "include/ast.h"
 #include "include/builtin.h"
-#include "include/dlist.h"
 #include "include/exec.h"
 #include "include/htab.h"
 #include "include/scope.h"
@@ -39,10 +38,11 @@ AST* exec_exp(AST* ast, Scope* parent) {
             return ast_init(
                 AST_TYPE_NUM, ast_num_data_init(*(ASTNumData*)ast->data)
             );
-        case AST_TYPE_VREF: return exec_vref(ast, parent);
+        case AST_TYPE_VREF:   return exec_vref(ast, parent);
-        case AST_TYPE_VDEF: return exec_vdef(ast, parent);
+        case AST_TYPE_VDEF:   return exec_vdef(ast, parent);
-        case AST_TYPE_FDEF: return exec_fdef(ast, parent);
+        case AST_TYPE_FDEF:   return exec_fdef(ast, parent);
-        default:            printf("what\n"); exit(1);
+        case AST_TYPE_LAMBDA: return exec_lambda(ast, parent);
+        default:              printf("what\n"); exit(1);
     }
 }
 
@@ -64,7 +64,8 @@ AST* exec_call(AST* ast, Scope* parent) {
     ASTCallData* data = (ASTCallData*)ast->data;
     size_t argc = data->argc;
     AST** argv = data->argv;
-    char* fname = data->to;
+    // char* fname = data->to;
+    AST* exp = data->to;
 
     ast->scope = parent;
 
@@ -79,7 +80,8 @@ AST* exec_call(AST* ast, Scope* parent) {
         case AST_TYPE_BIF:
             ASTBIFData bifdata = fdef->data;
             return bifdata(argc, argv, parent);
-        case AST_TYPE_FDEF: return exec_cf(fdef, argc, argv);
+        case AST_TYPE_FDEF:   return exec_cf(fdef, argc, argv);
+        case AST_TYPE_LAMBDA: return exec_lambda_call(fdef, argc, argv);
         default:
             return ast_init(AST_TYPE_EXC, ast_exc_data_init("Good job!", NULL));
     }
@@ -132,14 +134,29 @@ AST* exec_vref(AST* ast, Scope* parent) {
 AST* exec_fdef(AST* ast, Scope* parent) {
     ast->scope = scope_init(parent);
     ASTFDefData* fdef = (ASTFDefData*)ast->data;
-    log_dbgf("IS THIS SUSPICIOUS??? %i", fdef->body->type);
     AST* val = ast;
     char* key = fdef->name;
     scope_add(parent, key, val);
-    // TODO: Create lambda functions.
     return fdef->body; // Function definitions return function body.
 }
 
+AST* exec_lambda(AST* ast, Scope* parent) {
+    // Executing a lambda on its own with no arguments returns itself.
+    return ast;
+}
+
+AST* exec_lambda_call(AST* ast, size_t argc, AST** argv) {
+    Scope* callscope = scope_init(ast->scope);
+    ASTFDefData* lambda = (ASTFDefData*)ast->data;
+    for (int i = 0; i < argc; i++) {
+        char* key = ((ASTArgData*)lambda->argv[i]->data)->name;
+        AST* val = argv[i];
+        scope_add(callscope, key, val);
+    }
+
+    return exec_exp(lambda->body, callscope);
+}
+
 void exec_print(double n) { printf("= %lf\n", n); }
 
 inline void exec_new_scope(AST* ast, Scope* inherit) {

src/grammar.y

@@ -47,6 +47,8 @@
 
 %token NL // Newline.
 
+%token BACKSLASH
+
 %left ADD SUB
 %left MUL DIV
 %precedence NEG
@@ -124,12 +126,25 @@ block:
 exp:
     NUM { $$ = ast_init(AST_TYPE_NUM, ast_num_data_init($1)); }
 
-    // Function definitions.
+    // Function definitions. Convert to VDef of Lambda.
-    | WORD GROUPS arg GROUPE EQ exp {
+    | WORD GROUPS arg GROUPE exp {
-        size_t argc = $3->ln;
+        size_t parc = $3->ln;
-        AST** argv = $3->buf;
+        AST** parv = $3->buf;
         argarr_destroypsv($3);
-        $$ = ast_init(AST_TYPE_FDEF, ast_fdef_data_init($1, argc, argv, $6));
+        $$ = ast_init(AST_TYPE_VDEF, ast_vdef_data_init(
+            $1,
+            ast_init(AST_TYPE_LAMBDA, ast_lambda_data_init(
+                parc, parv, $5
+            )
+        ));
+    }
+
+    // Lambda definitions.
+    | BACKSLASH GROUPS arg GROUPE exp {
+        size_t parc = $3->ln;
+        AST** parv = $3->buf;
+        argarr_destroypsv($3);
+        $$ = ast_init(AST_TYPE_LAMBDA, ast_lambda_data_init(parc, parv, $5));
     }
 
     | BLOCKS block BLOCKE {

src/include/ast.h

@@ -18,13 +18,14 @@ typedef enum {
     AST_TYPE_LIST, // A list (variable size, variable type).
 
     // Misc. types.
-    AST_TYPE_BIF,   // Built-in function.
+    AST_TYPE_BIF,    // Built-in function.
-    AST_TYPE_CALL,  // A function call.
+    AST_TYPE_CALL,   // A function call.
-    AST_TYPE_VDEF,  // A variable definition.
+    AST_TYPE_VDEF,   // A variable definition.
-    AST_TYPE_VREF,  // A variable reference.
+    AST_TYPE_VREF,   // A variable reference.
-    AST_TYPE_BLOCK, // A block of code (scope).
+    AST_TYPE_BLOCK,  // A block of code (scope).
-    AST_TYPE_FDEF,  // A function definition.
+    AST_TYPE_FDEF,   // A function definition.
-    AST_TYPE_ARG,   // A definition argument.
+    AST_TYPE_LAMBDA, // An anonymous function definition.
+    AST_TYPE_ARG,    // A definition argument.
     AST_TYPE_MAX = AST_TYPE_ARG,
 } ASTType;
 
@@ -39,14 +40,8 @@ typedef struct {
 AST* ast_init(ASTType type, void* data);
 // Create a new `AST` with a specified scope.
 AST* ast_init_scope(ASTType type, void* data, Scope* scope);
-// Destroy an `AST`, recursively.
-void ast_destroy(AST* ast);
 // Destroy an `AST`.
-void ast_destroy_psv(AST* ast);
+void ast_destroy(AST* ast);
-// Print an `AST`, recursively.
-void ast_print(AST* ast);
-// Helper function to `ast_print()`, where `i` is indentation level.
-void ast_print_i(AST* ast, int i);
 
 // A number.
 typedef double ASTNumData;
@@ -55,20 +50,30 @@ typedef double ASTNumData;
 ASTNumData* ast_num_data_init(double val);
 // Destroy an `ASTNumData`.
 void ast_num_data_destroy(ASTNumData* num);
-// Print an `ASTNumData`.
-void ast_num_print(ASTNumData*, int i);
 
 // An exception.
 typedef struct ASTEXCDATA {
-    const char* msg;  // The exception message.
+    const char* msg; // The exception message.
-    AST* trace; // The previous exception.
+    AST* trace;      // The previous exception.
 } ASTExcData;
 // Create a new `ASTExecData. `msg` should be static.
 ASTExcData* ast_exc_data_init(const char* msg, AST* trace);
 // Destroy an `ASTExecData`.
 void ast_exc_data_destroy(ASTExcData* exc);
-// Print an `ASTExecData`.
+
-void ast_exc_print(ASTExcData*, int i);
+// Argument list as anonymous struct.
+#define ARGS                                                                   \
+    struct {                                                                   \
+        size_t argc;                                                           \
+        AST** argv;                                                            \
+    }
+
+// Parameter list as anonymous struct.
+#define PARS                                                                   \
+    struct {                                                                   \
+        size_t parc;                                                           \
+        AST** parv;                                                            \
+    }
 
 // A built-in function.
 typedef AST* (*ASTBIFData)(size_t argc, AST** argv, Scope* scope);
@@ -78,38 +83,41 @@ ASTBIFData* ast_bif_data_init(AST* fn(size_t, AST**, Scope*));
 // Destroy an `ASTBIFData`.
 void ast_bif_data_destroy(ASTBIFData* bif);
 
-// A call (to a function).
+// A lambda.
 typedef struct {
-    char* to;    // What the call's to.
+    PARS;      // The parameters the lambda can accept.
-    size_t argc; // Argument count.
+    AST* body; // The body expression to be executed.
-    AST** argv;  // Argument vector.
+} ASTLambdaData;
+
+// Creates a new `ASTLambdaData`.
+ASTLambdaData* ast_lambda_data_init(size_t parc, AST** parv, AST* body);
+// Destroy an `ASTLambdaData`.
+void ast_lambda_data_destroy(ASTLambdaData*);
+
+// A call.
+typedef struct {
+    ARGS;    // The arguments the call is made with.
+    AST* to; // The expression the call is to (probably either lambda or
+             // builtin).
 } ASTCallData;
 
 // Create a new `ASTCallData`.
-ASTCallData* ast_call_data_init(char* to, size_t argc, AST** argv);
+ASTCallData* ast_call_data_init(size_t argc, AST** argv, AST* to);
-// Destroy an `ASTCallData` recursively.
-void ast_call_data_destroy(ASTCallData* call);
 // Destroy an `ASTCallData`.
-void ast_call_data_destroy_psv(ASTCallData *call);
+void ast_call_data_destroy(ASTCallData* call);
-// Print an `ASTCallData`.
-void ast_call_print(ASTCallData*, int i);
 
-// A variable definition's data.
+// A variable definition. Associates a name with an expression.
 typedef struct {
     char* name;
-    AST* val;
+    AST* exp;
 } ASTVDefData;
 
 // Create a new `ASTVDefData`.
-ASTVDefData* ast_vdef_data_init(char* name, AST* val);
+ASTVDefData* ast_vdef_data_init(char* name, AST* exp);
-// Destroys the `ASTVDefData`, `ASTVDefData->name`, and `ASTVDefData->val`.
-void ast_vdef_data_destroy(ASTVDefData* vdef);
 // Destroy an `ASTVDefData`.
-void ast_vdef_data_destroy_psv(ASTVDefData* vdef);
+void ast_vdef_data_destroy(ASTVDefData* vdef);
-// Print an `ASTVDefData`.
-void ast_vdef_print(ASTVDefData*, int depth);
 
-// A variable reference's data.
+// A variable reference.
 typedef struct {
     char* to; // What the reference's to.
 } ASTVrefData;
@@ -118,8 +126,6 @@ typedef struct {
 ASTVrefData* ast_vref_data_init(char* to);
 // Destroy an `ASTVRefData`.
 void ast_vref_data_destroy(ASTVrefData* call);
-// Print an `ASTVRefData`.
-void ast_vref_print(ASTVrefData*, int i);
 
 // A code block.
 typedef struct {
@@ -132,15 +138,12 @@ ASTBlockData* ast_block_data_init(AST** inside, size_t ln);
 // Destroy an `ASTBlockData`, recursively.
 void ast_block_data_destroy(ASTBlockData* block);
 // Destroy an `ASTBlockData`.
-void ast_block_data_destroy_psv(ASTBlockData *block);
+void ast_block_data_destroy_psv(ASTBlockData* block);
-// Print an `ASTBlockData`.
-void ast_block_print(ASTBlockData*, int i);
 
 typedef struct {
-    char* name;  // Function name.
+    char* name; // Function name.
-    size_t argc; // Argument count.
+    ARGS;       // Function args.
-    AST** argv;  // Argument vector.
+    AST* body;  // Function body.
-    AST* body;   // Function body.
 } ASTFDefData;
 
 // Create a new `ASTFDefData`.
@@ -149,8 +152,6 @@ ASTFDefData* ast_fdef_data_init(char* name, size_t argc, AST** argv, AST* body);
 void ast_fdef_data_destroy(ASTFDefData* fdef);
 // Destroy an `ASTFDefData`.
 void ast_fdef_data_destroy_psv(ASTFDefData* fdef);
-// Print an `ASTFDefData`.
-void ast_fdef_print(ASTFDefData* fdef, int i);
 
 typedef struct {
     char* name; // Argument name.
@@ -160,9 +161,20 @@ typedef struct {
 ASTArgData* ast_arg_data_init(char* name);
 // Destroy an `ASTArgData`.
 void ast_arg_data_destroy(ASTArgData* arg);
-// Print an `ASTArgData`.
-void ast_arg_print(ASTArgData* arg, int i);
 
+/*
+// Represents a function as data.
+typedef struct {
+    ARGS;
+    AST* body;
+} ASTLambdaData;
+
+// Creates a new `ASTLambdaData`.
+ASTLambdaData* ast_lambda_data_init(size_t argc, AST** argv, AST* body);
+// Destroy an `ASTLambdaData`.
+void ast_lambda_data_destroy(ASTLambdaData*);
+
+*/
 // Find a name in the scope.
 AST* ast_find(Scope* scope, char* name);
 

src/include/ast_print.h

@@ -0,0 +1,38 @@
+#ifndef AST_PRINT_H
+#define AST_PRINT_H
+
+#include "ast.h"
+
+// Print an `AST`, recursively.
+void ast_print(AST* ast);
+// Helper function to `ast_print()`, where `i` is indentation level.
+void ast_print_i(AST* ast, int i);
+
+// Print an `ASTNumData`.
+void ast_num_print(ASTNumData*, int i);
+
+// Print an `ASTExecData`.
+void ast_exc_print(ASTExcData*, int i);
+
+// Print an `ASTCallData`.
+void ast_call_print(ASTCallData*, int i);
+
+// Print an `ASTVDefData`.
+void ast_vdef_print(ASTVDefData*, int depth);
+
+// Print an `ASTVRefData`.
+void ast_vref_print(ASTVrefData*, int i);
+
+// Print an `ASTBlockData`.
+void ast_block_print(ASTBlockData*, int i);
+
+// Print an `ASTFDefData`.
+void ast_fdef_print(ASTFDefData* fdef, int i);
+
+// Print an `ASTArgData`.
+void ast_arg_print(ASTArgData* arg, int i);
+
+// Print an `ASTLambdaData`.
+void ast_lambda_print(ASTLambdaData* arg, int i);
+
+#endif

src/include/exec.h

@@ -20,6 +20,10 @@ AST* exec_vdef(AST* ast, Scope* parent);
 AST* exec_vref(AST* ast, Scope* parent);
 // Execute a function definition.
 AST* exec_fdef(AST* ast, Scope* parent);
+// Execute a lambda expression.
+AST* exec_lambda(AST* ast, Scope* parent);
+// Execute a lambda call.
+AST* exec_lambda_call(AST* ast, size_t argc, AST** argv);
 // Print the result of an execution.
 void exec_print(double n);
 

src/include/util.h

@@ -1,6 +1,8 @@
 #ifndef UTIL_H
 #define UTIL_H
 
+#include <signal.h>
+
 // Most of this file is cursed printing macros for `ast_print()`. Do not attempt
 // to comprehend.
 
@@ -10,6 +12,9 @@
 // Get the length of an array.
 #define arrln(A) (sizeof(A)/sizeof(*A))
 
+// Trap GDB &c.
+#define TRAP() RAISE(SIGTRAP)
+
 #ifdef DBG // Debug macros
 
 // Log a message.

src/lexer.c

@@ -116,6 +116,7 @@ int yylex() {
         case '{':  return BLOCKS;
         case '}':  return BLOCKE;
         case '=':  return EQ;
+        case '\\': return BACKSLASH;
         default:   fprintf(stderr, "Unexpected character: %c\n", c);
     }
 

src/main.c

@@ -2,6 +2,7 @@
 #include <string.h>
 
 #include "include/ast.h"
+#include "include/ast_print.h"
 #include "include/dstr.h"
 #include "include/exec.h"
 #include "include/gc.h"

type-notes.md

@@ -0,0 +1,21 @@
+Primitive Types
+- num
+- bool
+- str
+
+```
+fact(x) = ? (x <= 1) 1 : f(x-1) * x
+> lambda
+fact(5) == 120
+> True
+```
+
+Ordered collections.
+| Name | Homogeneous | Fixed Size | Unique |
+|---|---|---|---|
+| Collection | No | No | No |
+| List |  Yes | No | No |
+| Array | Yes | Yes | No |
+| Group | No | Yes | No |
+| Set | Yes | No | Yes |
+| Perm | Yes | Yes | Yes |