94 lines
2.4 KiB
Zig
94 lines
2.4 KiB
Zig
const std = @import("std");
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const token = @import("token.zig");
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const main = @import("main.zig");
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const TokenList = std.ArrayList(token.Token);
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pub const Scanner = struct {
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source: []u8,
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tokens: TokenList,
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start: usize = 0,
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current: usize = 0,
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line: usize = 1,
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pub fn init(allocator: *std.mem.Allocator, data: []u8) Scanner {
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return Scanner{
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.source = data,
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.tokens = TokenList.init(allocator),
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};
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}
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fn isAtEnd(self: *Scanner) bool {
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return self.current >= self.source.len;
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}
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fn advance(self: *Scanner) u8 {
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self.current += 1;
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return self.source[self.current - 1];
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}
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fn currentLexeme(self: *Scanner) []u8 {
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return self.source[self.start..self.current];
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}
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fn addSimpleToken(self: *Scanner, ttype: token.TokenType) !void {
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try self.addToken(token.Token{
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.Simple = token.SimpleToken.init(
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ttype,
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self.currentLexeme(),
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self.line,
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{},
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),
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});
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}
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fn addToken(
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self: *Scanner,
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tok: token.Token,
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) !void {
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try self.tokens.append(tok);
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}
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fn scanToken(self: *Scanner) !void {
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var c = self.advance();
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switch (c) {
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'(' => try self.addSimpleToken(.LEFT_PAREN),
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')' => try self.addSimpleToken(.RIGHT_PAREN),
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'{' => try self.addSimpleToken(.LEFT_BRACE),
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'}' => try self.addSimpleToken(.RIGHT_BRACE),
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',' => try self.addSimpleToken(.COMMA),
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'.' => try self.addSimpleToken(.DOT),
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'-' => try self.addSimpleToken(.MINUS),
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'+' => try self.addSimpleToken(.PLUS),
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';' => try self.addSimpleToken(.SEMICOLON),
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'*' => try self.addSimpleToken(.STAR),
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else => {
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try main.doError(self.line, "Unexpected character");
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},
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}
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}
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pub fn scanTokens(self: *Scanner) !TokenList {
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// while we aren't at the end, we're still consuming
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// tokens.
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while (!self.isAtEnd()) {
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self.start = self.current;
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try self.scanToken();
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}
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try self.addToken(token.Token{
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.Simple = token.SimpleToken.init(
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.EOF,
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"",
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self.line,
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{},
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),
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});
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return self.tokens;
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}
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};
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