Implement interpreter

[zlox.git] / src / main.zig

diff --git a/src/main.zig b/src/main.zig
index ec4478bce4aa8e614b020308006ef128d46f51ae..1f02d3e7f89026fd72a6534bdf48eed06b9c7bc2 100644 (file)
--- a/src/main.zig
+++ b/src/main.zig
@@ -1,25 +1,37 @@
 const std = @import("std");
 const Allocator = std.mem.Allocator;
 const Scanner = @import("Scanner.zig");
+const Token = @import("Token.zig");
+const Parser = @import("Parser.zig");
+const Interpreter = @import("Interpreter.zig");
+const ErrorPayload = Interpreter.ErrorPayload;
 
+var interpreter: Interpreter = undefined;
 var hadError = false;
+var hadRuntimeError = false;
 
 pub fn main() !u8 {
     var gpa: std.heap.DebugAllocator(.{}) = .init;
     defer _ = gpa.deinit();
     const allocator = gpa.allocator();
+
     const args = try std.process.argsAlloc(allocator);
     defer std.process.argsFree(allocator, args);
 
+    var stdout_buffer: [1024]u8 = undefined;
+    var stdout_writer = std.fs.File.stdout().writer(&stdout_buffer);
+    const stdout = &stdout_writer.interface;
+    interpreter = Interpreter.init(allocator, stdout);
+    defer interpreter.deinit();
+
     if (args.len > 2) {
-        var stdout_writer = std.fs.File.stdout().writer(&.{});
-        const stdout = &stdout_writer.interface;
         try stdout.writeAll("Usage: zlox [script]\n");
+        try stdout.flush();
         return 64;
     } else if (args.len == 2) {
         return runFile(allocator, args[1]);
     } else {
-        try runPrompt(allocator);
+        try runPrompt(allocator, stdout);
     }
 
     return 0;
@@ -32,19 +44,19 @@ fn runFile(allocator: Allocator, path: []const u8) !u8 {
 
     // Indicate an error in the exit code.
     if (hadError) return 65;
+    if (hadRuntimeError) return 70;
 
     return 0;
 }
 
-fn runPrompt(allocator: Allocator) !void {
+fn runPrompt(allocator: Allocator, stdout: *std.Io.Writer) !void {
     var stdin_buffer: [1024]u8 = undefined;
     var stdin_reader = std.fs.File.stdin().reader(&stdin_buffer);
     const stdin = &stdin_reader.interface;
-    var stdout_writer = std.fs.File.stdout().writer(&.{});
-    const stdout = &stdout_writer.interface;
 
     while (true) {
         try stdout.writeAll("> ");
+        try stdout.flush();
         const line = try stdin.takeDelimiter('\n');
         if (line == null) break;
         try run(allocator, line.?);
@@ -53,17 +65,21 @@ fn runPrompt(allocator: Allocator) !void {
 }
 
 fn run(allocator: Allocator, source: []const u8) !void {
-    var scanner = Scanner.init(source);
-    const tokens = try scanner.scanTokens(allocator);
+    var scanner = Scanner.init(allocator, source);
+    const tokens = try scanner.scanTokens();
     defer allocator.free(tokens);
+    var parser = try Parser.init(allocator, tokens);
+    defer parser.deinit();
+    const expression = try parser.parse();
 
-    // For now, just print the tokens.
-    for (tokens) |token| {
-        std.debug.print("{f}\n", .{token});
-    }
+    // Stop if there was a syntax error.
+    if (hadError) return;
+
+    try interpreter.interpret(expression.?);
+    try interpreter.stdout.flush();
 }
 
-pub fn @"error"(line: u32, message: []const u8) !void {
+pub fn scanError(line: u32, message: []const u8) !void {
     try report(line, "", message);
 }
 
@@ -76,3 +92,17 @@ fn report(line: u32, where: []const u8, message: []const u8) !void {
     try stderr.flush();
     hadError = true;
 }
+
+pub fn parseError(allocator: Allocator, token: Token, message: []const u8) !void {
+    if (token.type == .eof) {
+        try report(token.line, " at end", message);
+    } else {
+        try report(token.line, try std.fmt.allocPrint(allocator, " at '{s}'", .{token.lexeme}), message);
+    }
+}
+
+pub fn runtimeError(err: ErrorPayload) !void {
+    try stderr.print("{s}\n[line {}]\n", .{ err.message, err.token.line });
+    try stderr.flush();
+    hadRuntimeError = true;
+}