Started adding scope.

Doesn't really do anything yet as blocks aren't fully implemented.

src/exec.c

@@ -4,64 +4,88 @@
 
 #include "include/ast.h"
 #include "include/exec.h"
+#include "include/stack.h"
 #include "include/util.h"
+#include "include/htab.h"
 
 extern AST* root;
 
-ASTNumData exec_exp(AST* ast) {
+ASTNumData exec_start(AST* ast) {
+    // The `Stack` of `HTab` that makes up the scope of any given `AST`.
+    Stack* scope = stack_init();
+
+    // Global scope. Just dummy values for testing.
+    HTab* global = htab_init();
+
+    // n = 42.02
+    char* name = malloc(2); // TODO: Write a macro for this pattern.
+    strcpy(name, "n");
+    AST* n = ast_init(AST_TYPE_VDEF, ast_vdef_data_init(name,
+        ast_init(AST_TYPE_NUM, ast_num_data_init(42.02))
+    ));
+
+    htab_ins(global, ((ASTVDefData*)n->data)->name, ((ASTVDefData*)n->data)->val);
+
+    // Push global namespace to `scope`.
+    stack_push(scope, global);
+
+    return exec_exp(ast, scope);
+}
+
+ASTNumData exec_exp(AST* ast, Stack* scope) {
     log_dbg("Started execution.");
     switch (ast->type) {
-        case AST_TYPE_CALL: return exec_call(ast);
+        case AST_TYPE_CALL: return exec_call(ast, scope);
         case AST_TYPE_NUM:  return *(ASTNumData*)ast->data;
-        case AST_TYPE_VREF: return exec_vref(ast);
-        case AST_TYPE_VDEF: return exec_vdef(ast);
+        case AST_TYPE_VREF: return exec_vref(ast, scope);
+        case AST_TYPE_VDEF: return exec_vdef(ast, scope);
         default:            printf("what\n");
                             exit(1);
     }
 }
 
-ASTNumData exec_call(AST* ast) {
+ASTNumData exec_call(AST* ast, Stack* scope) {
     log_dbg("Started call execution.");
     fflush(stdout);
     ASTCallData* calldata = (ASTCallData*)ast->data;
     if (calldata->argc >= 1) {
     if (!strcmp(calldata->to, "sum")) {
-        double total = exec_exp(calldata->argv[0]);
+        double total = exec_exp(calldata->argv[0], scope);
 
         for (
             size_t i = 1;
             i < calldata->argc;
-            total += exec_exp(calldata->argv[i++])
+            total += exec_exp(calldata->argv[i++], scope)
         );
 
         return total;
     } else if (!strcmp(calldata->to, "sub")) {
-        double total = exec_exp(calldata->argv[0]);
+        double total = exec_exp(calldata->argv[0], scope);
 
         for (
             size_t i = 1;
             i < calldata->argc;
-            total -= exec_exp(calldata->argv[i++])
+            total -= exec_exp(calldata->argv[i++], scope)
         );
 
         return total;
     } else if (!strcmp(calldata->to, "mul")) {
-        double total = exec_exp(calldata->argv[0]);
+        double total = exec_exp(calldata->argv[0], scope);
 
         for (
             size_t i = 1;
             i < calldata->argc;
-            total *= exec_exp(calldata->argv[i++])
+            total *= exec_exp(calldata->argv[i++], scope)
         );
 
         return total;
     } else if (!strcmp(calldata->to, "div")) {
-        double total = exec_exp(calldata->argv[0]);
+        double total = exec_exp(calldata->argv[0], scope);
 
         for (
             size_t i = 1;
             i < calldata->argc;
-            total /= exec_exp(calldata->argv[i++])
+            total /= exec_exp(calldata->argv[i++], scope)
         );
 
         return total;
@@ -69,14 +93,25 @@ ASTNumData exec_call(AST* ast) {
     return -1000;
 }
 
-ASTNumData exec_vdef(AST* ast) {
+ASTNumData exec_vdef(AST* ast, Stack* scope) {
     ASTVDefData* data = (ASTVDefData*) ast->data;
     AST* val = data->val;
-    return exec_exp(val);
+    char* key = data->name;
+    htab_ins(scope->val[0], key, val);
+    return exec_exp(val, scope);
 }
 
-ASTNumData exec_vref(AST* ast) {
-    return *ast_num_data_init(42.42);
+ASTNumData exec_vref(AST* ast, Stack* scope) {
+    log_dbg("attempting to reference var");
+    ASTVrefData* vref = (ASTVrefData*) ast->data;
+
+    char* key = vref->to;
+    AST* val;
+
+    val = htab_get(scope->val[0], key);
+    if (val != NULL) return exec_exp(val, scope); else log_dbg("didn't find def");
+
+    return *ast_num_data_init(101.0);
 }
 
 void exec_print(double n) { printf("= %lf\n", n); }

src/grammar.y

@@ -124,9 +124,9 @@ exp:
     }
 
     // Variable reference.
-    //| WORD {
-    //    $$ = ast_init(AST_TYPE_VREF, ast_vref_data_init($1));
-    //}
+    | WORD {
+        $$ = ast_init(AST_TYPE_VREF, ast_vref_data_init($1));
+    }
 
     | WORD GROUPS arg GROUPE {
         size_t argc = $3->ln;

src/include/exec.h

@@ -2,11 +2,15 @@
 #define EXEC_H
 
 #include "ast.h"
+#include "stack.h"
 
-ASTNumData exec_exp(AST* ast);
-ASTNumData exec_call(AST* ast);
-ASTNumData exec_vref(AST* ast);
-ASTNumData exec_vdef(AST* ast);
+
+// Start executing at the root of the AST. Initialize the `scope`.
+ASTNumData exec_start(AST* ast);
+ASTNumData exec_exp(AST* ast, Stack* scope);
+ASTNumData exec_call(AST* ast, Stack* scope);
+ASTNumData exec_vref(AST* ast, Stack* scope);
+ASTNumData exec_vdef(AST* ast, Stack* scope);
 void exec_print(double n);
 
 #endif

src/include/stack.h

@@ -10,14 +10,15 @@ typedef struct {
     void* val[STACK_MAX];   // The stack itself.
 } Stack;
 
+// Create a `Stack`.
 Stack* stack_init();
-// Destroy a stack.
-// Note that `stack->i` must be `0`.
+// Destroy a `Stack`.
+// Note that `->i` must be `0`, i.e. the `Stack` must be empty.
 void stack_destroy(Stack* stack);
 
-// Push a value to the stack.
+// Push a value to the `Stack`.
 void stack_push(Stack* stack, void* val);
-// Pop a value from the stack.
+// Pop a value from the `Stack`.
 void* stack_pop(Stack* stack);
 
 #endif

src/main.c

@@ -19,7 +19,7 @@ int main(int argc, char** argv) {
 
     if (argc - 1 && strlen(argv[1]) > 0 && (inp = argv[1]) && !yyparse()) {
         log_dbg("Parsed successfully!\n");
-        exec_print(exec_exp(root));
+        exec_print(exec_start(root));
         ast_destroy(root);
         exit(0);
     }
@@ -51,7 +51,7 @@ int main(int argc, char** argv) {
                 log_dbg("Parsed successfully!\n");
             } else printf("Parse error.\n");
 
-            exec_print(exec_exp(root));
+            exec_print(exec_start(root));
 #ifdef DBG
             ast_print(root);
 #endif