Add parsing for def/set! expressions

4 files changed, 99 insertions, 15 deletions

diff --git a/src/lexer.c b/src/lexer.c
index cbcc175..704ee66 100755
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -13,6 +13,8 @@ static const char* token_str[] = {
     [TOKEN_FALSE]   = "TOKEN_FALSE",
     [TOKEN_LAMBDA]  = "TOKEN_LAMBDA",
     [TOKEN_IF]      = "TOKEN_IF",
+    [TOKEN_DEF]     = "TOKEN_DEF",
+    [TOKEN_SET]     = "TOKEN_SET",
     [TOKEN_EOF]     = "TOKEN_EOF",
 };
 
@@ -128,6 +130,8 @@ find_primitive_type(const StringView value) {
     if (TOKEN_IS_KEYWORD(value, "false")) { return TOKEN_FALSE; }
     if (TOKEN_IS_KEYWORD(value, "lambda")) { return TOKEN_LAMBDA; }
     if (TOKEN_IS_KEYWORD(value, "if")) { return TOKEN_IF; }
+    if (TOKEN_IS_KEYWORD(value, "def")) { return TOKEN_DEF; }
+    if (TOKEN_IS_KEYWORD(value, "set!")) { return TOKEN_SET; }
 
     return TOKEN_SYMBOL;
 }
diff --git a/src/lexer.h b/src/lexer.h
index 4798a2b..f187526 100755
--- a/src/lexer.h
+++ b/src/lexer.h
@@ -21,6 +21,8 @@ typedef enum TokenType {
     // Keywords.
     TOKEN_LAMBDA,
     TOKEN_IF,
+    TOKEN_DEF,
+    TOKEN_SET,
 
     // End of file.
     TOKEN_EOF,
diff --git a/src/parser.c b/src/parser.c
index 5551dd2..f831e50 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -122,7 +122,7 @@ parse_lambda(Parser *parser, Errors *errors) {
 Object *
 parse_if(Parser *parser, Errors *errors) {
     Token start = next_token(parser);
-    Object *obj_if = object_alloc(start, OBJ_TYPE_IF);
+    Object *ret = object_alloc(start, OBJ_TYPE_IF);
 
     Token tok = peek_token(parser);
     if (tok.type == TOKEN_RPAREN) {
@@ -134,7 +134,7 @@ parse_if(Parser *parser, Errors *errors) {
         });
         return NULL;
     }
-    obj_if->condition = parse_tree(parser, errors);
+    ret->condition = parse_tree(parser, errors);
 
     tok = peek_token(parser);
     if (tok.type == TOKEN_RPAREN) {
@@ -146,16 +146,16 @@ parse_if(Parser *parser, Errors *errors) {
         });
         return NULL;
     }
-    obj_if->expr_true = parse_tree(parser, errors);
+    ret->expr_true = parse_tree(parser, errors);
 
     // Optional else expression.
     tok = peek_token(parser);
     if (tok.type == TOKEN_RPAREN) {
         next_token(parser);
-        obj_if->expr_false = NULL;
-        return obj_if;
+        ret->expr_false = NULL;
+        return ret;
     }
-    obj_if->expr_false = parse_tree(parser, errors);
+    ret->expr_false = parse_tree(parser, errors);
 
     tok = peek_token(parser);
     if (tok.type != TOKEN_RPAREN) {
@@ -168,7 +168,62 @@ parse_if(Parser *parser, Errors *errors) {
         return NULL;
     }
     next_token(parser);
-    return obj_if;
+    return ret;
+}
+
+Object *
+parse_var(Parser *parser, Errors *errors) {
+    Token start = next_token(parser);
+    ObjectType type = start.type == TOKEN_DEF ? OBJ_TYPE_DEF : OBJ_TYPE_SET;
+    Object *ret = object_alloc(start, type);
+
+    // Variable name.
+    Token tok = peek_token(parser);
+    if (tok.type == TOKEN_RPAREN) {
+        error_push(errors, (Error){
+            .type = ERR_TYPE_PARSER,
+            .value = ERR_NOT_ENOUGH_ARGS,
+            .line = tok.line,
+            .col = tok.col,
+        });
+        return NULL;
+    }
+    if (tok.type != TOKEN_SYMBOL) {
+        error_push(errors, (Error){
+            .type = ERR_TYPE_PARSER,
+            .value = ERR_WRONG_ARG_TYPE,
+            .line = tok.line,
+            .col = tok.col,
+        });
+        return NULL;
+    }
+    ret->var_name = parse_tree(parser, errors);
+
+    // Variable value (expression).
+    tok = peek_token(parser);
+    if (tok.type == TOKEN_RPAREN) {
+        error_push(errors, (Error){
+            .type = ERR_TYPE_PARSER,
+            .value = ERR_NOT_ENOUGH_ARGS,
+            .line = tok.line,
+            .col = tok.col,
+        });
+        return NULL;
+    }
+    ret->var_expr = parse_tree(parser, errors);
+
+    tok = peek_token(parser);
+    if (tok.type != TOKEN_RPAREN) {
+        error_push(errors, (Error){
+            .type = ERR_TYPE_PARSER,
+            .value = ERR_TOO_MANY_ARGS,
+            .line = tok.line,
+            .col = tok.col,
+        });
+        return NULL;
+    }
+    next_token(parser);
+    return ret;
 }
 
 Object *
@@ -188,12 +243,10 @@ parse_list(Parser *parser, Errors *errors) {
             });
             return NULL;
         } break;
-        case TOKEN_LAMBDA: {
-            return parse_lambda(parser, errors);
-        } break;
-        case TOKEN_IF: {
-            return parse_if(parser, errors);
-        } break;
+        case TOKEN_LAMBDA: { return parse_lambda(parser, errors); } break;
+        case TOKEN_IF: { return parse_if(parser, errors); } break;
+        case TOKEN_DEF: { return parse_var(parser, errors); } break;
+        case TOKEN_SET: { return parse_var(parser, errors); } break;
         default: break;
     }
 
@@ -386,7 +439,7 @@ object_display(Object *obj) {
             printf(")");
         } break;
         case OBJ_TYPE_LAMBDA: {
-            printf("#{ lambda( ");
+            printf("#{ lambda ( ");
             for (size_t i = 0; i < array_size(obj->params); i++) {
                 object_display(obj->params[i]);
                 printf(" ");
@@ -408,7 +461,21 @@ object_display(Object *obj) {
                 object_display(obj->expr_false);
             }
             printf(" }");
-        };
+        } break;
+        case OBJ_TYPE_DEF: {
+            printf("#{ def ");
+            object_display(obj->var_name);
+            printf(" ");
+            object_display(obj->var_expr);
+            printf(" }");
+        } break;
+        case OBJ_TYPE_SET: {
+            printf("#{ set! ");
+            object_display(obj->var_name);
+            printf(" ");
+            object_display(obj->var_expr);
+            printf(" }");
+        } break;
     }
     return;
 }
diff --git a/src/parser.h b/src/parser.h
index b2b07c8..14d9df5 100755
--- a/src/parser.h
+++ b/src/parser.h
@@ -13,6 +13,8 @@ typedef enum ObjectType {
     OBJ_TYPE_PAIR,
     OBJ_TYPE_LAMBDA,
     OBJ_TYPE_IF,
+    OBJ_TYPE_DEF,
+    OBJ_TYPE_SET,
 } ObjectType;
 
 typedef struct Object {
@@ -43,6 +45,13 @@ typedef struct Object {
              struct Object *expr_true;
              struct Object *expr_false;
          };
+
+         // OBJ_TYPE_DEF
+         // OBJ_TYPE_SET
+         struct {
+             struct Object *var_name;
+             struct Object *var_expr;
+         };
     };
 
     size_t line;
@@ -71,6 +80,8 @@ Object * parse_bool(Token tok);
 Object * parse_fixnum(Token tok);
 Object * parse_list(Parser *parser, Errors *errors);
 Object * parse_lambda(Parser *parser, Errors *errors);
+Object * parse_if(Parser *parser, Errors *errors);
+Object * parse_var(Parser *parser, Errors *errors);
 Root * parse(Token *tokens, Errors *errors);
 
 // Object operations.