compiler: can now implement functions

examples/test.lisp

@@ -1,3 +1,5 @@
 (define x 1)
 
-(display (sum x 1))
+(define inc (lambda (n) (sum n 1)))
+
+(display (inc x))

src/compiler.c

@@ -1,5 +1,13 @@
 #include "compiler.h"
 
+typedef struct sc_global {
+  sc_ast* ast;
+  char* name;
+} sc_global;
+
+int n_globals = 0;
+sc_global** globals = NULL;
+
 char* get_prelude() {
   char* str;
   size_t size;
@@ -25,7 +33,25 @@ char* get_prelude() {
 
 char* compile_expr(sc_ast* ast);
 
+void add_global(char* name, sc_ast* ast) {
+  globals = realloc(globals, ++n_globals*sizeof(sc_global*));
+  sc_global* g = malloc(sizeof(sc_global));
+  g->name = name;
+  g->ast = ast;
+  globals[n_globals-1] = g;
+}
+
+char* compile_lambda(sc_ast* ast) {
+  char* name = ast->children[1]->value;
+  add_global(name, ast->children[2]);
+  return NULL;
+}
+
 char* compile_define(sc_ast* ast) {
+  if (ast->children[2]->tag == LIST &&
+      !(strcmp(ast->children[2]->children[0]->value, "lambda"))) {
+    return compile_lambda(ast);
+  }
   char* rhs = compile_expr(ast->children[2]);
   char* name = ast->children[1]->value;
   char* res = malloc(strlen(rhs)+strlen(name)+10);
@@ -60,6 +86,33 @@ char* compile_list(sc_ast* ast) {
   return res;
 }
 
+char* compile_global(sc_global* global) {
+  int i;
+  char* tmp;
+  char* res = malloc(strlen(global->name)+18);
+  sprintf(res, "Value %s(", global->name);
+  int reslen = strlen(res)+1;
+
+  sc_ast* args = global->ast->children[1];
+  for (i = 0; i < args->n_children; i++) {
+    if (i > 0) {
+      reslen += strlen(args->children[i]->value)+8;
+      res = realloc(res, reslen);
+      snprintf(res, reslen, "%s, Value %s", res, args->children[i]->value);
+    } else {
+      reslen += strlen(args->children[i]->value)+6;
+      res = realloc(res, reslen);
+      snprintf(res, reslen, "%sValue %s", res, args->children[i]->value);
+    }
+  }
+  tmp = compile_expr(global->ast->children[2]);
+  reslen += strlen(tmp)+14;
+  res = realloc(res, reslen);
+  snprintf(res, reslen, "%s) { return %s; }", res, tmp);
+
+  return res;
+}
+
 char* compile(sc_ast* ast) {
   int i;
   char* tmp;
@@ -77,8 +130,16 @@ char* compile(sc_ast* ast) {
     snprintf(main, mainlen, "%s;%s", main, tmp);
   }
 
-  res = realloc(res, reslen+mainlen+2);
-  snprintf(res, reslen+mainlen+2, "%s;%s;}", res, main);
+  for (i = 0; i < n_globals; i++) {
+    tmp = compile_global(globals[i]);
+    if (!tmp) continue;
+    reslen += strlen(tmp);
+    res = realloc(res, reslen);
+    snprintf(res, reslen, "%s%s", res, tmp);
+  }
+
+  res = realloc(res, reslen+mainlen+1);
+  snprintf(res, reslen+mainlen+1, "%s%s;}", res, main);
 
   return res;
 }