实现 12.4 词法：25 关键字、小写折叠、TIME 字面量、lex error。
- Lexer.h/cpp：关键字表（大小写不敏感折小写）、(* *) 注释不嵌套、整数/T# 段式字面量、最长匹配符号 - token 带 source_file + 行列（起始位置，修了消费后行列的偏差） - lexer_test：75 断言（line1 三文件 token 流 21/34/27、大小写、符号、注释、行列、5 类负例） - Doc/compiler/词法.md：设计文档 + 执行计划
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/**
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* @file Lexer.cpp
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* @brief 词法分析（12.4 实现）
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* @date 2026-08-19
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* @brief ST 子集词法分析
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* @author
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* @date 2026-08-21
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*/
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#include "compiler/Lexer.h"
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#include <cctype>
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#include <cstdio>
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#include <fstream>
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#include <string>
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namespace compiler {
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namespace {
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// 25 个关键字：小写键 → Tok（大小写不敏感，见 Doc/compiler/词法.md）
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const struct {
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const char* key;
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Tok tok;
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} kKeywords[] = {
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{"program", Tok::PROGRAM},
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{"function", Tok::FUNCTION},
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{"function_block", Tok::FUNCTION_BLOCK},
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{"end_program", Tok::END_PROGRAM},
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{"end_function", Tok::END_FUNCTION},
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{"end_function_block", Tok::END_FUNCTION_BLOCK},
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{"var", Tok::VAR},
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{"var_input", Tok::VAR_INPUT},
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{"var_output", Tok::VAR_OUTPUT},
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{"var_global", Tok::VAR_GLOBAL},
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{"var_external", Tok::VAR_EXTERNAL},
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{"end_var", Tok::END_VAR},
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{"bool", Tok::BOOL},
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{"int", Tok::INT},
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{"time", Tok::TIME},
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{"if", Tok::IF},
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{"elsif", Tok::ELSIF},
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{"else", Tok::ELSE},
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{"end_if", Tok::END_IF},
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{"while", Tok::WHILE},
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{"end_while", Tok::END_WHILE},
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{"and", Tok::AND},
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{"or", Tok::OR},
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{"not", Tok::NOT},
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{"true", Tok::TRUE},
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{"false", Tok::FALSE},
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{"ton", Tok::TON},
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{"tof", Tok::TOF},
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{"ctu", Tok::CTU},
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};
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// TIME 字面量单位 → 毫秒倍数（不敏感）
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int64_t time_unit_ms(const std::string& unit) {
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if (unit == "ms") return 1;
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if (unit == "s") return 1000;
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if (unit == "m") return 60000;
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if (unit == "h") return 3600000;
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if (unit == "d") return 86400000;
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return -1;
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}
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class Lexer {
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public:
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Lexer(const std::string& source_file, const std::string& content,
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std::vector<Token>* out, std::string* err)
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: src_(content), sf_(source_file), out_(out), err_(err),
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pos_(0), line_(1), col_(1) {}
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bool run() {
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while (true) {
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if (!skip_space_and_comments()) {
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return false;
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}
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if (pos_ >= src_.size()) {
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push(Tok::END, "", 0);
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return true;
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}
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if (!lex_one()) {
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return false;
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}
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}
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}
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private:
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bool fail(const std::string& msg) {
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if (err_) {
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char buf[128];
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std::snprintf(buf, sizeof buf, " (%s, line %u, col %u)",
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sf_.c_str(), line_, col_);
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*err_ = "lex error: " + msg + buf;
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}
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return false;
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}
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char cur() const { return src_[pos_]; }
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bool at_end() const { return pos_ >= src_.size(); }
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void advance() {
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if (cur() == '\n') {
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++line_;
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col_ = 1;
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} else {
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++col_;
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}
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++pos_;
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}
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// 跳过空白与 (* *) 注释（不嵌套）；未闭合返回 false
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bool skip_space_and_comments() {
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while (!at_end()) {
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if (std::isspace(static_cast<unsigned char>(cur()))) {
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advance();
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} else if (cur() == '(' && pos_ + 1 < src_.size() &&
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src_[pos_ + 1] == '*') {
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advance();
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advance(); // 跳过 "(*"
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bool closed = false;
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while (!at_end()) {
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if (cur() == '*' && pos_ + 1 < src_.size() &&
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src_[pos_ + 1] == ')') {
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advance();
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advance();
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closed = true;
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break;
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}
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advance();
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}
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if (!closed) {
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return fail("unterminated comment");
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}
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} else {
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break;
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}
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}
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return true;
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}
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void push(Tok type, const std::string& text, int64_t value) {
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Token t;
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t.type = type;
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t.text = text;
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t.int_value = value;
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t.source_file = sf_;
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t.line = tok_line_;
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t.col = tok_col_;
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out_->push_back(t);
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}
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bool lex_one() {
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// 记录本 token 起始位置（push 时消费已经推进了行列）
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tok_line_ = line_;
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tok_col_ = col_;
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const char c = cur();
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// TIME 字面量：T#（大小写不敏感）优先于标识符
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if ((c == 't' || c == 'T') && pos_ + 1 < src_.size() && src_[pos_ + 1] == '#') {
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return lex_time();
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}
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// 标识符 / 关键字（统一折小写）
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if (std::isalpha(static_cast<unsigned char>(c)) || c == '_') {
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const uint32_t start = pos_;
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while (!at_end() &&
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(std::isalnum(static_cast<unsigned char>(cur())) || cur() == '_')) {
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advance();
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}
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std::string word = src_.substr(start, pos_ - start);
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for (char& ch : word) {
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ch = static_cast<char>(std::tolower(static_cast<unsigned char>(ch)));
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}
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for (const auto& kw : kKeywords) {
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if (word == kw.key) {
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push(kw.tok, kw.key, 0);
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return true;
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}
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}
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push(Tok::IDENT, word, 0);
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return true;
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}
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// 整数
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if (std::isdigit(static_cast<unsigned char>(c))) {
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const uint32_t start = pos_;
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while (!at_end() && std::isdigit(static_cast<unsigned char>(cur()))) {
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advance();
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}
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const std::string digits = src_.substr(start, pos_ - start);
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uint64_t v = 0;
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for (const char ch : digits) {
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const uint64_t d = static_cast<uint64_t>(ch - '0');
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if (v > (static_cast<uint64_t>(INT64_MAX) - d) / 10) {
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return fail("integer literal too large");
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}
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v = v * 10 + d;
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}
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push(Tok::INT_LIT, digits, static_cast<int64_t>(v));
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return true;
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}
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// 符号（最长匹配优先）
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switch (c) {
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case ':':
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if (pos_ + 1 < src_.size() && src_[pos_ + 1] == '=') {
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advance();
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advance();
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push(Tok::ASSIGN, ":=", 0);
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} else {
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advance();
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push(Tok::COLON, ":", 0);
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}
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return true;
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case '=':
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advance();
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push(Tok::EQ, "=", 0);
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return true;
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case '<':
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if (pos_ + 1 < src_.size() && src_[pos_ + 1] == '=') {
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advance();
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advance();
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push(Tok::LE, "<=", 0);
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} else if (pos_ + 1 < src_.size() && src_[pos_ + 1] == '>') {
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advance();
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advance();
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push(Tok::NE, "<>", 0);
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} else {
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advance();
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push(Tok::LT, "<", 0);
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}
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return true;
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case '>':
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if (pos_ + 1 < src_.size() && src_[pos_ + 1] == '=') {
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advance();
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advance();
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push(Tok::GE, ">=", 0);
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} else {
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advance();
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push(Tok::GT, ">", 0);
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}
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return true;
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case '+':
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advance();
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push(Tok::PLUS, "+", 0);
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return true;
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case '-':
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advance();
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push(Tok::MINUS, "-", 0);
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return true;
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case '*':
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advance();
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push(Tok::STAR, "*", 0);
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return true;
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case '/':
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advance();
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push(Tok::SLASH, "/", 0);
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return true;
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case '(':
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advance();
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push(Tok::LPAREN, "(", 0);
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return true;
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case ')':
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advance();
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push(Tok::RPAREN, ")", 0);
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return true;
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case ',':
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advance();
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push(Tok::COMMA, ",", 0);
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return true;
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case ';':
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advance();
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push(Tok::SEMI, ";", 0);
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return true;
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case '.':
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advance();
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push(Tok::DOT, ".", 0);
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return true;
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default:
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return fail(std::string("illegal character '") + c + "'");
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}
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}
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// T#<int><unit>... 段式解析，累加毫秒
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bool lex_time() {
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const uint32_t start = pos_;
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advance(); // T
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advance(); // #
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int64_t total = 0;
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bool any = false;
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while (!at_end() && std::isdigit(static_cast<unsigned char>(cur()))) {
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uint64_t v = 0;
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while (!at_end() && std::isdigit(static_cast<unsigned char>(cur()))) {
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const uint64_t d = static_cast<uint64_t>(cur() - '0');
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if (v > (static_cast<uint64_t>(INT64_MAX) - d) / 10) {
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return fail("bad time literal");
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}
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v = v * 10 + d;
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advance();
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}
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std::string unit;
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while (!at_end() && std::isalpha(static_cast<unsigned char>(cur()))) {
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unit += static_cast<char>(
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std::tolower(static_cast<unsigned char>(cur())));
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advance();
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}
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const int64_t mult = time_unit_ms(unit);
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if (mult < 0) {
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return fail("bad time literal");
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}
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total += static_cast<int64_t>(v) * mult;
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any = true;
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}
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if (!any) {
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return fail("bad time literal");
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}
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push(Tok::TIME_LIT, src_.substr(start, pos_ - start), total);
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return true;
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}
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const std::string& src_;
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const std::string& sf_;
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std::vector<Token>* out_;
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std::string* err_;
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size_t pos_;
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uint32_t line_;
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uint32_t col_;
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uint32_t tok_line_ = 1;
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uint32_t tok_col_ = 1;
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};
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} // namespace
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bool lex(const std::string& source_file, const std::string& content,
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std::vector<Token>* out, std::string* err) {
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out->clear();
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Lexer l(source_file, content, out, err);
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return l.run();
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}
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bool lex_file(const std::string& path, std::vector<Token>* out, std::string* err) {
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std::ifstream in(path, std::ios::binary);
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if (!in) {
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if (err) {
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*err = "lex error: cannot open file (" + path + ")";
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}
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return false;
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}
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std::string content((std::istreambuf_iterator<char>(in)),
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std::istreambuf_iterator<char>());
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return lex(path, content, out, err);
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}
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} // namespace compiler
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