334 lines
9.2 KiB
C++
334 lines
9.2 KiB
C++
/*
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Copyright (c) 2014 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#include <cctype>
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#include <string>
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#include "util/exception.h"
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#include "frontends/lean/scanner.h"
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#include "frontends/lean/parser_config.h"
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namespace lean {
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void scanner::next() {
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lean_assert(m_curr != EOF);
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m_curr = m_stream.get();
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m_spos++;
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}
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void scanner::check_not_eof(char const * error_msg) const {
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if (curr() == EOF) throw_exception(error_msg);
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}
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[[ noreturn ]] void scanner::throw_exception(char const * msg) const {
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throw parser_exception(msg, m_stream_name.c_str(), m_sline, m_spos);
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}
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auto scanner::read_string() -> token_kind {
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static char const * end_error_msg = "unexpected end of string";
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lean_assert(curr() == '\"');
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next();
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m_buffer.clear();
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while (true) {
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check_not_eof(end_error_msg);
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update_line();
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char c = curr();
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if (c == '\"') {
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next();
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return token_kind::String;
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} else if (c == '\\') {
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next();
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check_not_eof(end_error_msg);
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c = curr();
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if (c != '\\' && c != '\"' && c != 'n')
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throw_exception("invalid escape sequence");
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if (c == 'n')
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c = '\n';
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}
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m_buffer += c;
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next();
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}
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}
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bool scanner::is_next_digit() {
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lean_assert(curr() != EOF);
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char c = m_stream.get();
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bool r = std::isdigit(c);
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m_stream.unget();
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return r;
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}
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auto scanner::read_number() -> token_kind {
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lean_assert('0' <= curr() && curr() <= '9');
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mpq q(1);
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m_num_val = curr() - '0';
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next();
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bool is_decimal = false;
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while (true) {
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char c = curr();
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if ('0' <= c && c <= '9') {
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m_num_val = 10*m_num_val + (c - '0');
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if (is_decimal)
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q *= 10;
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next();
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} else if (c == '.') {
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// Num. is not a decimal. It should be at least Num.0
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if (is_next_digit()) {
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if (is_decimal)
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break;
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is_decimal = true;
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next();
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} else {
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break;
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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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if (is_decimal)
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m_num_val /= q;
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return is_decimal ? token_kind::Decimal : token_kind::Numeral;
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}
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void scanner::read_single_line_comment() {
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while (true) {
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if (curr() == '\n') {
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new_line();
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next();
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return;
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} else if (curr() == EOF) {
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return;
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} else {
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next();
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}
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}
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}
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// Try to consume str, return true if success.
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// Throw a parser exception error_msg if end of file is found
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bool scanner::consume(char const * str, char const * error_msg) {
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if (curr() == str[0]) {
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next();
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unsigned i = 1;
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while (true) {
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if (!str[i])
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return true;
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check_not_eof(error_msg);
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update_line();
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if (curr_next() != str[i])
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return false;
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i++;
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}
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} else {
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return false;
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}
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}
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static char const * g_begin_comment_block = "(--";
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static char const * g_end_comment_block = "--)";
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void scanner::read_comment_block() {
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static char const * end_error_msg = "unexpected end of comment block";
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unsigned nesting = 1;
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while (true) {
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if (consume(g_begin_comment_block, end_error_msg)) {
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nesting++;
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}
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if (consume(g_end_comment_block, end_error_msg)) {
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nesting--;
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if (nesting == 0)
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return;
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}
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check_not_eof(end_error_msg);
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update_line();
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next();
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}
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}
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// Read until the end_str is found, store all characters (not including end_str) in m_buffer.
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// Throw a parser exception error_msg if end of file is found before end_str.
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void scanner::read_until(char const * end_str, char const * error_msg) {
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lean_assert(end_str);
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lean_assert(end_str[0]);
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m_buffer.clear();
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while (true) {
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check_not_eof(error_msg);
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update_line();
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char c = curr_next();
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if (c == end_str[0]) {
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m_aux_buffer.clear();
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m_aux_buffer += c;
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unsigned i = 1;
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while (true) {
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if (!end_str[i])
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return;
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check_not_eof(error_msg);
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update_line();
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c = curr_next();
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if (c != end_str[i]) {
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m_buffer += m_aux_buffer;
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break;
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}
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i++;
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}
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} else {
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m_buffer += c;
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}
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}
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}
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auto scanner::read_script_block() -> token_kind {
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read_until("*)", "unexpected end of script");
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return token_kind::ScriptBlock;
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}
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static bool is_id_first(char c) { return std::isalpha(c) || c == '_'; }
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static bool is_id_rest(char c) { return std::isalnum(c) || c == '_' || c == '\''; }
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void scanner::move_back(std::streamoff offset) {
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if (offset != 0) {
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if (curr() == EOF) {
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m_curr = 0;
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m_stream.clear();
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m_spos--;
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}
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m_stream.seekg(offset, std::ios_base::cur);
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m_spos += offset;
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next();
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}
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}
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bool scanner::is_next_id_rest() {
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lean_assert(curr() != EOF);
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char c = m_stream.get();
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bool r = is_id_rest(c);
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m_stream.unget();
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return r;
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}
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auto scanner::read_key_cmd_id() -> token_kind {
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static char const * error_msg = "unexpected token";
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char c = curr();
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unsigned num_cs = 1; // number of characters read
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token_table const * it = find(*m_tokens, c);
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token_info const * info = nullptr;
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unsigned key_size = 0;
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if (it) {
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info = value_of(*it);
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if (info)
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key_size = 1;
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}
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std::string & id_part = m_buffer;
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bool is_id = is_id_first(c);
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unsigned id_size = 0;
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if (is_id) {
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m_name_val = name();
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id_part.clear();
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id_part.push_back(c);
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id_size = 1;
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}
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while (it || is_id) {
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next();
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c = curr();
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if (c != EOF)
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num_cs++;
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if (is_id) {
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if (is_id_rest(c)) {
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id_part.push_back(c);
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id_size++;
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} else if (c == '.' && is_next_id_rest()) {
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m_name_val = name(m_name_val, id_part.c_str());
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id_size++;
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id_part.clear();
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} else {
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is_id = false;
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m_name_val = name(m_name_val, id_part.c_str());
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if (!it)
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return token_kind::Identifier;
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}
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}
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if (it) {
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it = find(*it, c);
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if (it) {
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if (auto new_info = value_of(*it)) {
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info = new_info;
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key_size = num_cs;
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}
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} else if (!is_id) {
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if (id_size > key_size) {
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move_back(static_cast<std::streamoff>(id_size) - static_cast<std::streamoff>(num_cs));
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return token_kind::Identifier;
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} else if (info) {
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move_back(static_cast<std::streamoff>(key_size) - static_cast<std::streamoff>(num_cs));
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m_token_info = info;
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return info->is_command() ? token_kind::CommandKeyword : token_kind::Keyword;
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}
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}
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}
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}
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throw_exception(error_msg);
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}
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static name g_begin_script_tk("(*");
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static name g_begin_comment_tk("--");
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static name g_begin_comment_block_tk("(--");
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auto scanner::scan(environment const & env) -> token_kind {
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m_tokens = &get_parser_config(env).m_tokens;
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while (true) {
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char c = curr();
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m_pos = m_spos;
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m_line = m_sline;
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switch (c) {
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case ' ': case '\r': case '\t':
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next();
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break;
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case '\n':
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next(); new_line();
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break;
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case '\"':
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return read_string();
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case -1:
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return token_kind::Eof;
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default:
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if (std::isdigit(c)) {
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return read_number();
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} else {
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token_kind k = read_key_cmd_id();
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if (k == token_kind::Keyword) {
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// We treat '(--', '(*', '--' as "keywords.
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name const & n = m_token_info->value();
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if (n == g_begin_comment_tk)
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read_single_line_comment();
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else if (n == g_begin_comment_block_tk)
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read_comment_block();
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else if (n == g_begin_script_tk)
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return read_script_block();
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else
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return k;
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} else {
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return k;
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}
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}
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}
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}
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}
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scanner::scanner(std::istream & strm, char const * strm_name):
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m_tokens(nullptr), m_stream(strm), m_spos(0), m_sline(1), m_curr(0), m_pos(0), m_line(1),
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m_token_info(nullptr) {
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m_stream_name = strm_name ? strm_name : "[unknown]";
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next();
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}
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std::ostream & operator<<(std::ostream & out, scanner::token_kind k) {
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out << static_cast<unsigned>(k);
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return out;
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}
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}
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