diff --git a/Makefile b/Makefile
index aaa244b..d09ec66 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,9 @@ CFLAGS = -std=c17 -Wall -Wextra -Wpedantic -Wconversion -pedantic -pedantic-erro
 
 CFILES = \
 	main.c \
+	parser.c \
+	checker.c \
+	vm.c \
 
 OBJECT_FILES = $(patsubst %.c,%.o,$(CFILES))
 
diff --git a/checker.c b/checker.c
new file mode 100644
index 0000000..c1dfa96
--- /dev/null
+++ b/checker.c
@@ -0,0 +1 @@
+#include "parser.h"
diff --git a/main.c b/main.c
index 50c765e..61ce2e2 100644
--- a/main.c
+++ b/main.c
@@ -1,3 +1,25 @@
+#include "parser.h"
+#include <stddef.h>
 #include <stdio.h>
+#include <string.h>
 
-int main(void) { printf("hello world\n"); }
+bool lexer_debug = false;
+
+void print_error(const char* message, Pos pos)
+{
+    fprintf(
+        stderr, "\x1b[31merror\x1b[0m: %s, on line %d\n", message, pos.line);
+}
+
+int main(void)
+{
+
+    char test_program[] = " if a == true { (1) += 2; } ";
+
+    Parser parser;
+    parser_construct(&parser, test_program, strlen(test_program));
+
+    ASTNode* ast = parser_parse_statements(&parser);
+
+    printf("ast = %d\n", ast->node_type);
+}
diff --git a/parser.c b/parser.c
index 89d2ede..be9a96e 100644
--- a/parser.c
+++ b/parser.c
@@ -1,5 +1,6 @@
 #include "parser.h"
 #include <stddef.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -65,7 +66,8 @@ static inline TokenType match_id_to_token_type(
     const char* source, size_t length, struct MatchIdToTokenTypeCase cases[])
 {
     for (size_t i = 0; cases[i].keyword != NULL; ++i) {
-        if (strncmp(source, cases[i].keyword, length) == 0) {
+        if (strlen(cases[i].keyword) <= length
+            && strncmp(source, cases[i].keyword, length) == 0) {
             return cases[i].token_type;
         }
     }
@@ -87,7 +89,9 @@ static inline Token lex_id_or_keyword(Lexer* lexer)
                 { "and", TokenType_And },
                 { "or", TokenType_Or },
                 { "if", TokenType_If },
+                { "else", TokenType_Else },
                 { "loop", TokenType_Loop },
+                { "let", TokenType_Let },
                 { "fn", TokenType_Fn },
                 { "return", TokenType_Return },
                 { "break", TokenType_Break },
@@ -134,11 +138,23 @@ Token lexer_next(Lexer* lexer)
     }
     if (c >= '1' && c <= '9') {
         lexer_step(lexer);
-        while (!lexer_done(lexer) && c >= '1' && c <= '9') {
+        while (!lexer_done(lexer) && lexer_current(lexer) >= '0'
+            && lexer_current(lexer) <= '9') {
             lexer_step(lexer);
         }
         return lexer_token(lexer, TokenType_Int, pos);
     }
+    if (c == '-') {
+        lexer_step(lexer);
+        if (lexer_current(lexer) == '=') {
+            lexer_step(lexer);
+            return lexer_token(lexer, TokenType_MinusEqual, pos);
+        } else if (lexer_current(lexer) == '>') {
+            lexer_step(lexer);
+            return lexer_token(lexer, TokenType_MinusGT, pos);
+        }
+        return lexer_token(lexer, TokenType_Minus, pos);
+    }
     switch (c) {
         case '0':
             return lex_single_char(lexer, TokenType_Int);
@@ -161,9 +177,6 @@ Token lexer_next(Lexer* lexer)
         case '+':
             return lex_single_or_double_char(
                 lexer, TokenType_Plus, '=', TokenType_PlusEqual);
-        case '-':
-            return lex_single_or_double_char(
-                lexer, TokenType_Minus, '=', TokenType_MinusEqual);
         case '*':
             return lex_single_or_double_char(
                 lexer, TokenType_Asterisk, '=', TokenType_AsteriskEqual);
@@ -292,6 +305,10 @@ void ast_node_free(ASTNode* node)
             break;
         case ASTNodeType_Int:
             break;
+        case ASTNodeType_Group:
+            ast_node_free(node->group_value);
+            break;
+        case ASTNodeType_Statements:
         case ASTNodeType_Block:
             for (size_t i = 0; i < node->statements.length; ++i) {
                 ast_node_free(node->statements.data[i]);
@@ -329,23 +346,24 @@ void ast_node_free(ASTNode* node)
             ast_node_free(node->assign_node.value);
             break;
         case ASTNodeType_Let:
-            if (node->let_node.id != NULL) {
-                free(node->let_node.id);
-            }
+            ast_node_free(node->let_node.id);
             ast_node_free(node->let_node.value);
             break;
         case ASTNodeType_Break:
             break;
         case ASTNodeType_Fn:
-            if (node->fn_node.id != NULL) {
-                free(node->fn_node.id);
-            }
+            ast_node_free(node->fn_node.id);
             for (size_t i = 0; i < node->fn_node.params.length; ++i) {
                 ast_node_free(node->fn_node.params.data[i]);
             }
             ast_node_vec_destroy(&node->fn_node.params);
             ast_node_free(node->fn_node.body);
             break;
+        case ASTNodeType_Return:
+            if (node->return_node.value != NULL) {
+                ast_node_free(node->return_node.value);
+            }
+            break;
     }
     free(node);
 }
@@ -360,7 +378,7 @@ void parser_construct(Parser* parser, const char* text, size_t text_length)
         .failed = false,
     };
     lexer_construct(&parser->lexer, text, text_length);
-    parser->current = lexer_next(&parser->lexer);
+    parser_step(parser);
 }
 
 bool parser_failed(const Parser* parser) { return parser->failed; }
@@ -375,11 +393,379 @@ bool parser_done(const Parser* parser)
     return parser->current.token_type == TokenType_EOF;
 }
 
-ASTNode* parser_parse(Parser* parser) { return parser_parse_expr(parser); }
-
-ASTNode* parser_parse_expr(Parser* parser)
+ASTNode* parser_parse_statements(Parser* parser)
 {
-    return parser_parse_operand(parser);
+    Pos pos = parser->current.pos;
+    ASTNodeVec statements;
+    ast_node_vec_construct(&statements);
+    while (!parser_done(parser)) {
+        ASTNode* statement = parser_parse_statement(parser);
+        ast_node_vec_push(&statements, statement);
+    }
+    return ast_node_new(
+        ASTNodeType_Statements, pos, (ASTNode) { .statements = statements });
+}
+
+ASTNode* parser_parse_statement(Parser* parser)
+{
+    if (parser->current.token_type == TokenType_Fn) {
+        return parser_parse_fn(parser);
+    } else if (parser->current.token_type == TokenType_If) {
+        return parser_parse_if(parser);
+    } else if (parser->current.token_type == TokenType_Loop) {
+        return parser_parse_loop(parser);
+    } else {
+        ASTNode* statement = parser_parse_single_line_statement(parser);
+        if (parser->current.token_type != TokenType_Semicolon) {
+            parser->failed = true;
+            print_error("parser: expected ';'", parser->current.pos);
+        }
+        parser_step(parser);
+        return statement;
+    }
+}
+
+ASTNode* parser_parse_fn(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    parser_step(parser);
+    if (parser->current.token_type != TokenType_Id) {
+        parser->failed = true;
+        print_error("parser: expected 'id'", parser->current.pos);
+        return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+    }
+    ASTNode* id = parser_parse_id(parser);
+    if (parser->current.token_type != TokenType_LParen) {
+        parser->failed = true;
+        print_error("parser: expected '('", parser->current.pos);
+        return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+    }
+    parser_step(parser);
+    ASTNodeVec params;
+    ast_node_vec_construct(&params);
+    if (!parser_done(parser)
+        && parser->current.token_type != TokenType_RParen) {
+        if (parser->current.token_type != TokenType_Id) {
+            parser->failed = true;
+            print_error("parser: expected 'id'", parser->current.pos);
+            return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+        }
+        ast_node_vec_push(&params, parser_parse_id(parser));
+        while (parser->current.token_type == TokenType_Comma) {
+            parser_step(parser);
+            if (parser->current.token_type == TokenType_RParen) {
+                break;
+            }
+            if (parser->current.token_type != TokenType_Id) {
+                parser->failed = true;
+                print_error("parser: expected 'id'", parser->current.pos);
+                return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+            }
+            ast_node_vec_push(&params, parser_parse_id(parser));
+        }
+    }
+    if (parser->current.token_type != TokenType_RParen) {
+        parser->failed = true;
+        print_error("parser: expected ')'", parser->current.pos);
+        return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+    }
+    parser_step(parser);
+    if (parser->current.token_type != TokenType_LBrace) {
+        parser->failed = true;
+        print_error("parser: expected '{'", parser->current.pos);
+        return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+    }
+    ASTNode* body = parser_parse_block(parser);
+    return ast_node_new(ASTNodeType_Fn, pos, (ASTNode) {
+        .fn_node = (ASTFnNode) {
+            .id = id,
+            .params = params,
+            .body = body,
+        },
+    });
+}
+
+ASTNode* parser_parse_single_line_statement(Parser* parser)
+{
+    if (parser->current.token_type == TokenType_Let) {
+        return parser_parse_let(parser);
+    } else if (parser->current.token_type == TokenType_Return) {
+        return parser_parse_return(parser);
+    } else if (parser->current.token_type == TokenType_Break) {
+        return parser_parse_break(parser);
+    } else {
+        return parser_parse_assign(parser);
+    }
+}
+
+ASTNode* parser_parse_let(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    parser_step(parser);
+    if (parser->current.token_type != TokenType_Id) {
+        parser->failed = true;
+        print_error("parser: expected 'id'", parser->current.pos);
+        return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+    }
+    ASTNode* id = parser_parse_id(parser);
+    if (parser->current.token_type != TokenType_Equal) {
+        parser->failed = true;
+        print_error("parser: expected '='", parser->current.pos);
+        return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+    }
+    parser_step(parser);
+    ASTNode* value = parser_parse_expr(parser);
+    return ast_node_new(ASTNodeType_Let, pos, (ASTNode) {
+        .let_node = (ASTLetNode) {
+            .id = id,
+            .value = value,
+        },
+    });
+}
+
+ASTNode* parser_parse_return(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    parser_step(parser);
+    ASTNode* value = NULL;
+    if (parser->current.token_type != TokenType_Semicolon) {
+        value = parser_parse_expr(parser);
+    }
+    return ast_node_new(ASTNodeType_Return, pos, (ASTNode) {
+        .return_node = (ASTReturnNode) {
+            .value = value,
+        },
+    });
+}
+
+ASTNode* parser_parse_break(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    parser_step(parser);
+    return ast_node_new(ASTNodeType_Return, pos, (ASTNode) { 0 });
+}
+
+ASTNode* parser_parse_assign(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    ASTNode* subject = parser_parse_expr(parser);
+    int assign_type = -1;
+    if (parser->current.token_type == TokenType_Equal) {
+        assign_type = AssignType_Assign;
+    } else if (parser->current.token_type == TokenType_PlusEqual) {
+        assign_type = AssignType_Add;
+    } else if (parser->current.token_type == TokenType_MinusEqual) {
+        assign_type = AssignType_Subtract;
+    } else if (parser->current.token_type == TokenType_AsteriskEqual) {
+        assign_type = AssignType_Multiply;
+    }
+    if (assign_type == -1) {
+        return subject;
+    }
+    parser_step(parser);
+    return ast_node_new(ASTNodeType_Assign, pos, (ASTNode) {
+        .assign_node = (ASTAssignNode) {
+            .assign_type = (AssignType)assign_type,
+            .subject = subject,
+            .value = parser_parse_expr(parser),
+        },
+    });
+}
+
+ASTNode* parser_parse_expr(Parser* parser) { return parser_parse_or(parser); }
+
+static inline ASTNode* binary_node(
+    Pos pos, BinaryType binary_type, ASTNode* left, ASTNode* right)
+{
+    return ast_node_new(ASTNodeType_Binary, pos, (ASTNode) {
+        .binary_node = (ASTBinaryNode) {
+            .binary_type = binary_type,
+            .left = left,
+            .right = right,
+        },
+    });
+}
+
+ASTNode* parser_parse_or(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    ASTNode* left = parser_parse_and(parser);
+    while (parser->current.token_type == TokenType_Or) {
+        parser_step(parser);
+        left = binary_node(pos, BinaryType_Or, left, parser_parse_and(parser));
+    }
+    return left;
+}
+
+ASTNode* parser_parse_and(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    ASTNode* left = parser_parse_equality(parser);
+    while (parser->current.token_type == TokenType_And) {
+        parser_step(parser);
+        left = binary_node(
+            pos, BinaryType_And, left, parser_parse_equality(parser));
+    }
+    return left;
+}
+
+ASTNode* parser_parse_equality(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    ASTNode* left = parser_parse_comparison(parser);
+    if (parser->current.token_type == TokenType_EqualEqual) {
+        parser_step(parser);
+        return binary_node(
+            pos, BinaryType_EE, left, parser_parse_comparison(parser));
+    } else if (parser->current.token_type == TokenType_ExclamationEqual) {
+        parser_step(parser);
+        return binary_node(
+            pos, BinaryType_NE, left, parser_parse_comparison(parser));
+    } else {
+        return left;
+    }
+}
+
+ASTNode* parser_parse_comparison(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    ASTNode* left = parser_parse_term(parser);
+    while (!parser_done(parser)) {
+        if (parser->current.token_type == TokenType_LT) {
+            parser_step(parser);
+            return binary_node(
+                pos, BinaryType_LT, left, parser_parse_term(parser));
+        } else if (parser->current.token_type == TokenType_LTEqual) {
+            parser_step(parser);
+            return binary_node(
+                pos, BinaryType_LTE, left, parser_parse_term(parser));
+        } else if (parser->current.token_type == TokenType_GT) {
+            parser_step(parser);
+            return binary_node(
+                pos, BinaryType_GT, left, parser_parse_term(parser));
+        } else if (parser->current.token_type == TokenType_GTEqual) {
+            parser_step(parser);
+            return binary_node(
+                pos, BinaryType_GTE, left, parser_parse_term(parser));
+        } else {
+            break;
+        }
+    }
+    return left;
+}
+
+ASTNode* parser_parse_term(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    ASTNode* left = parser_parse_factor(parser);
+    while (!parser_done(parser)) {
+        if (parser->current.token_type == TokenType_Plus) {
+            parser_step(parser);
+            return binary_node(
+                pos, BinaryType_Add, left, parser_parse_factor(parser));
+        } else if (parser->current.token_type == TokenType_Minus) {
+            parser_step(parser);
+            return binary_node(
+                pos, BinaryType_Subtract, left, parser_parse_factor(parser));
+        } else {
+            break;
+        }
+    }
+    return left;
+}
+
+ASTNode* parser_parse_factor(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    ASTNode* left = parser_parse_unary(parser);
+    while (!parser_done(parser)) {
+        if (parser->current.token_type == TokenType_Asterisk) {
+            parser_step(parser);
+            return binary_node(
+                pos, BinaryType_Multiply, left, parser_parse_unary(parser));
+        } else {
+            break;
+        }
+    }
+    return left;
+}
+
+ASTNode* parser_parse_unary(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    if (parser->current.token_type == TokenType_Not) {
+        parser_step(parser);
+        return ast_node_new(ASTNodeType_Unary, pos, (ASTNode) {
+            .unary_node = (ASTUnaryNode) {
+                .unary_type = UnaryType_Not,
+                .subject = parser_parse_unary(parser),
+            },
+        });
+    } else if (parser->current.token_type == TokenType_Minus) {
+        parser_step(parser);
+        return ast_node_new(ASTNodeType_Unary, pos, (ASTNode) {
+            .unary_node = (ASTUnaryNode) {
+                .unary_type = UnaryType_Negate,
+                .subject = parser_parse_unary(parser),
+            },
+        });
+    } else {
+        return parser_parse_index_call(parser);
+    }
+}
+
+ASTNode* parser_parse_index_call(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    ASTNode* subject = parser_parse_operand(parser);
+    while (!parser_done(parser)) {
+        if (parser->current.token_type == TokenType_LParen) {
+            parser_step(parser);
+            ASTNodeVec args;
+            ast_node_vec_construct(&args);
+            if (!parser_done(parser)
+                && parser->current.token_type != TokenType_RParen) {
+                ast_node_vec_push(&args, parser_parse_expr(parser));
+                while (parser->current.token_type == TokenType_Comma) {
+                    parser_step(parser);
+                    if (parser->current.token_type == TokenType_RParen) {
+                        break;
+                    }
+                    ast_node_vec_push(&args, parser_parse_expr(parser));
+                }
+            }
+            if (parser->current.token_type != TokenType_RParen) {
+                parser->failed = true;
+                print_error("parser: expected ')'", parser->current.pos);
+                return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+            }
+            parser_step(parser);
+            subject = ast_node_new(ASTNodeType_Call, pos, (ASTNode) {
+                .call_node = (ASTCallNode) {
+                    .subject = subject,
+                    .args = args,
+                },
+            });
+        } else if (parser->current.token_type == TokenType_LBracket) {
+            parser_step(parser);
+            ASTNode* value = parser_parse_expr(parser);
+            if (parser->current.token_type != TokenType_RBracket) {
+                parser->failed = true;
+                print_error("parser: expected ']'", parser->current.pos);
+                return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+            }
+            parser_step(parser);
+            subject = ast_node_new(ASTNodeType_Index, pos, (ASTNode) {
+                .index_node = (ASTIndexNode) {
+                    .subject = subject,
+                    .value = value,
+                },
+            });
+        } else {
+            break;
+        }
+    }
+    return subject;
 }
 
 ASTNode* parser_parse_operand(Parser* parser)
@@ -393,14 +779,17 @@ ASTNode* parser_parse_operand(Parser* parser)
         case TokenType_Int:
             return parser_parse_int(parser);
         case TokenType_LParen:
+            return parser_parse_group(parser);
         case TokenType_LBrace:
+            return parser_parse_block(parser);
         case TokenType_If:
+            return parser_parse_if(parser);
         case TokenType_Loop:
+            return parser_parse_loop(parser);
         default:
             parser->failed = true;
-            print_error("expected operand", pos);
+            print_error("parser: expected operand", pos);
             return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
-            break;
     }
 }
 
@@ -430,11 +819,14 @@ ASTNode* parser_parse_group(Parser* parser)
     ASTNode* expr = parser_parse_expr(parser);
     if (parser->current.token_type != TokenType_RParen) {
         parser->failed = true;
-        print_error("parser: expected ')'", pos);
+        print_error("parser: expected ')'", parser->current.pos);
         return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
     }
     parser_step(parser);
-    return expr;
+    return ast_node_new(ASTNodeType_Group, pos,
+        (ASTNode) {
+            .group_value = expr,
+        });
 }
 
 ASTNode* parser_parse_block(Parser* parser)
@@ -450,7 +842,7 @@ ASTNode* parser_parse_block(Parser* parser)
     }
     if (parser->current.token_type != TokenType_RBrace) {
         parser->failed = true;
-        print_error("parser: expected '}'", pos);
+        print_error("parser: expected '}'", parser->current.pos);
         return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
     }
     parser_step(parser);
@@ -458,6 +850,49 @@ ASTNode* parser_parse_block(Parser* parser)
         ASTNodeType_Block, pos, (ASTNode) { .statements = statements });
 }
 
-ASTNode* parser_parse_if(Parser* parser);
+ASTNode* parser_parse_if(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    parser_step(parser);
+    ASTNode* condition = parser_parse_expr(parser);
+    if (parser->current.token_type != TokenType_LBrace) {
+        parser->failed = true;
+        print_error("parser: expected '{'", parser->current.pos);
+        return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+    }
+    ASTNode* truthy = parser_parse_block(parser);
+    ASTNode* falsy = NULL;
+    if (parser->current.token_type == TokenType_Else) {
+        parser_step(parser);
+        if (parser->current.token_type != TokenType_LBrace) {
+            parser->failed = true;
+            print_error("parser: expected '{'", parser->current.pos);
+            return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+        }
+        falsy = parser_parse_block(parser);
+    }
+    return ast_node_new(ASTNodeType_If, pos, (ASTNode) {
+        .if_node = (ASTIfNode) {
+            .condition = condition,
+            .truthy = truthy,
+            .falsy = falsy,
+        },
+    });
+}
 
-ASTNode* parser_parse_loop(Parser* parser);
+ASTNode* parser_parse_loop(Parser* parser)
+{
+    Pos pos = parser->current.pos;
+    parser_step(parser);
+    if (parser->current.token_type != TokenType_RBrace) {
+        parser->failed = true;
+        print_error("parser: expected '}'", parser->current.pos);
+        return ast_node_new(ASTNodeType_Error, pos, (ASTNode) { 0 });
+    }
+    ASTNode* body = parser_parse_block(parser);
+    return ast_node_new(ASTNodeType_Loop, pos, (ASTNode) {
+        .loop_node = (ASTLoopNode) { 
+            .body = body,
+        },
+    });
+}
diff --git a/parser.h b/parser.h
index 955cef0..813db4a 100644
--- a/parser.h
+++ b/parser.h
@@ -21,7 +21,9 @@ typedef enum {
     TokenType_And,
     TokenType_Or,
     TokenType_If,
+    TokenType_Else,
     TokenType_Loop,
+    TokenType_Let,
     TokenType_Fn,
     TokenType_Return,
     TokenType_Break,
@@ -37,6 +39,7 @@ typedef enum {
     TokenType_PlusEqual,
     TokenType_Minus,
     TokenType_MinusEqual,
+    TokenType_MinusGT,
     TokenType_Asterisk,
     TokenType_AsteriskEqual,
     TokenType_Equal,
@@ -79,6 +82,7 @@ typedef enum {
     ASTNodeType_Error,
     ASTNodeType_Id,
     ASTNodeType_Int,
+    ASTNodeType_Group,
     ASTNodeType_Block,
     ASTNodeType_If,
     ASTNodeType_Loop,
@@ -90,6 +94,8 @@ typedef enum {
     ASTNodeType_Let,
     ASTNodeType_Break,
     ASTNodeType_Fn,
+    ASTNodeType_Return,
+    ASTNodeType_Statements,
 } ASTNodeType;
 
 typedef struct ASTNode ASTNode;
@@ -137,15 +143,15 @@ typedef struct {
 typedef enum {
     BinaryType_And,
     BinaryType_Or,
-    BinaryType_Add,
-    BinaryType_Subtract,
-    BinaryType_Multiply,
     BinaryType_EE,
     BinaryType_NE,
     BinaryType_LT,
     BinaryType_GT,
     BinaryType_LTE,
     BinaryType_GTE,
+    BinaryType_Add,
+    BinaryType_Subtract,
+    BinaryType_Multiply,
 } BinaryType;
 
 typedef struct {
@@ -168,22 +174,27 @@ typedef struct {
 } ASTAssignNode;
 
 typedef struct {
-    char* id;
+    ASTNode* id;
     ASTNode* value;
 } ASTLetNode;
 
 typedef struct {
-    char* id;
+    ASTNode* id;
     ASTNodeVec params;
     ASTNode* body;
 } ASTFnNode;
 
+typedef struct {
+    ASTNode* value;
+} ASTReturnNode;
+
 struct ASTNode {
     ASTNodeType node_type;
     Pos pos;
     union {
         char* id_value;
         int int_value;
+        ASTNode* group_value;
         ASTNodeVec statements;
         ASTIfNode if_node;
         ASTLoopNode loop_node;
@@ -194,6 +205,7 @@ struct ASTNode {
         ASTAssignNode assign_node;
         ASTLetNode let_node;
         ASTFnNode fn_node;
+        ASTReturnNode return_node;
     };
 };
 
@@ -212,9 +224,23 @@ void parser_construct(Parser* parser, const char* text, size_t text_length);
 bool parser_failed(const Parser* parser);
 void parser_step(Parser* parser);
 bool parser_done(const Parser* parser);
-ASTNode* parser_parse(Parser* parser);
+ASTNode* parser_parse_statements(Parser* parser);
 ASTNode* parser_parse_statement(Parser* parser);
+ASTNode* parser_parse_fn(Parser* parser);
+ASTNode* parser_parse_single_line_statement(Parser* parser);
+ASTNode* parser_parse_let(Parser* parser);
+ASTNode* parser_parse_return(Parser* parser);
+ASTNode* parser_parse_break(Parser* parser);
+ASTNode* parser_parse_assign(Parser* parser);
 ASTNode* parser_parse_expr(Parser* parser);
+ASTNode* parser_parse_or(Parser* parser);
+ASTNode* parser_parse_and(Parser* parser);
+ASTNode* parser_parse_equality(Parser* parser);
+ASTNode* parser_parse_comparison(Parser* parser);
+ASTNode* parser_parse_term(Parser* parser);
+ASTNode* parser_parse_factor(Parser* parser);
+ASTNode* parser_parse_unary(Parser* parser);
+ASTNode* parser_parse_index_call(Parser* parser);
 ASTNode* parser_parse_operand(Parser* parser);
 ASTNode* parser_parse_id(Parser* parser);
 ASTNode* parser_parse_int(Parser* parser);
@@ -223,4 +249,11 @@ ASTNode* parser_parse_block(Parser* parser);
 ASTNode* parser_parse_if(Parser* parser);
 ASTNode* parser_parse_loop(Parser* parser);
 
+typedef struct {
+    int _a;
+} Checker;
+
+void checker_construct(Checker* checker);
+void checker_(Checker* checker);
+
 #endif
diff --git a/vm.c b/vm.c
new file mode 100644
index 0000000..d3561cc
--- /dev/null
+++ b/vm.c
@@ -0,0 +1,16 @@
+#include "vm.h"
+#include <stdlib.h>
+
+void vm_construct(
+    VM* vm, const Op* program, size_t program_size, size_t stack_size)
+{
+    *vm = (VM) {
+        .program = program,
+        .program_size = program_size,
+        .pc = 0,
+        .stack = malloc(sizeof(Value) * stack_size),
+        .stack_size = stack_size,
+        .sp = 0,
+        .bp = 0,
+    };
+}
diff --git a/vm.h b/vm.h
new file mode 100644
index 0000000..8617b15
--- /dev/null
+++ b/vm.h
@@ -0,0 +1,70 @@
+#ifndef VM_H
+#define VM_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+typedef enum {
+    OpType_Nop,
+    OpType_PushNull,
+    OpType_PushInt,
+    OpType_PushBool,
+    OpType_PushPtr,
+    OpType_Pop,
+    OpType_LoadLocal,
+    OpType_StoreLocal,
+    OpType_Jump,
+    OpType_JumpIf,
+    OpType_Load,
+    OpType_Store,
+    OpType_Call,
+    OpType_Return,
+    OpType_And,
+    OpType_Or,
+    OpType_EE,
+    OpType_NE,
+    OpType_LT,
+    OpType_GT,
+    OpType_LTE,
+    OpType_GTE,
+    OpType_Add,
+    OpType_Subtract,
+    OpType_Multiply,
+    OpType_Not,
+    OpType_Negate,
+} OpType;
+
+typedef uint32_t Op;
+
+typedef enum {
+    ValueType_Null,
+    ValueType_Int,
+    ValueType_Bool,
+    ValueType_Ptr,
+} ValueType;
+
+typedef struct Value Value;
+
+struct Value {
+    ValueType type;
+    union {
+        int int_value;
+        bool bool_value;
+        void* ptr_value;
+    };
+};
+
+typedef struct {
+    const Op* program;
+    size_t program_size;
+    size_t pc;
+    Value* stack;
+    size_t stack_size;
+    size_t sp;
+    size_t bp;
+} VM;
+
+void vm_construct(
+    VM* vm, const Op* program, size_t program_size, size_t stack_size);
+
+#endif