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Diffstat (limited to 'build2/lexer.hxx')
| -rw-r--r-- | build2/lexer.hxx | 205 |
1 files changed, 0 insertions, 205 deletions
diff --git a/build2/lexer.hxx b/build2/lexer.hxx deleted file mode 100644 index b71167a..0000000 --- a/build2/lexer.hxx +++ /dev/null @@ -1,205 +0,0 @@ -// file : build2/lexer.hxx -*- C++ -*- -// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd -// license : MIT; see accompanying LICENSE file - -#ifndef BUILD2_LEXER_HXX -#define BUILD2_LEXER_HXX - -#include <stack> - -#include <libbutl/char-scanner.mxx> - -#include <build2/types.hxx> -#include <build2/utility.hxx> - -#include <build2/token.hxx> -#include <build2/diagnostics.hxx> - -namespace build2 -{ - // Context-dependent lexing mode. In the value mode we don't treat certain - // characters (e.g., '+', '=') as special so that we can use them in the - // variable values, e.g., 'foo = g++'. In contrast, in the variable mode, we - // restrict certain character (e.g., '/') from appearing in the name. The - // attribute mode is like value except it doesn't treat '{' and '}' as - // special (so we cannot have name groups in attributes). The eval mode is - // used in the evaluation context. Quoted modes are internal and should not - // be set explicitly. - // - // Note that the normal, value, and eval modes split words separated by the - // pair character (to disable pairs one can pass '\0' as a pair character). - // - // The alternnative modes must be set manually. The value mode automatically - // expires after the end of the line. The attribute mode expires after the - // closing ']'. The variable mode expires after the word token. And the eval - // mode expires after the closing ')'. - // - // Note that normally it is only safe to switch mode when the current token - // is not quoted (or, more generally, when you are not in the double-quoted - // mode) unless the mode treats the double-quote as a separator (e.g., - // variable name mode). Failed that your mode (which now will be the top of - // the mode stack) will prevent proper recognition of the closing quote. - // - - // Extendable/inheritable enum-like class. - // - struct lexer_mode: lexer_mode_base - { - using base_type = lexer_mode_base; - - enum - { - normal = base_type::value_next, - variable, - value, - attribute, - eval, - single_quoted, - double_quoted, - buildspec, - - value_next - }; - - lexer_mode () = default; - lexer_mode (value_type v): base_type (v) {} - lexer_mode (base_type v): base_type (v) {} - }; - - class lexer: public butl::char_scanner - { - public: - // If escape is not NULL then only escape sequences with characters from - // this string are considered "effective escapes" with all others passed - // through as is. Note that the escape string is not copied. - // - lexer (istream& is, - const path& name, - uint64_t line = 1, // Start line in the stream. - const char* escapes = nullptr) - : lexer (is, name, line, escapes, true /* set_mode */) {} - - const path& - name () const {return name_;} - - // Note: sets mode for the next token. The second argument can be used to - // specifythe pair separator character (if the mode supports pairs). If - // escapes not specified, then inherit the current mode's (thought a mode - // can also override it). - // - virtual void - mode (lexer_mode, - char pair_separator = '\0', - optional<const char*> escapes = nullopt); - - // Expire the current mode early. - // - void - expire_mode () {state_.pop ();} - - lexer_mode - mode () const {return state_.top ().mode;} - - char - pair_separator () const {return state_.top ().sep_pair;} - - // Scanner. Note that it is ok to call next() again after getting eos. - // - // If you extend the lexer and add a custom lexer mode, then you must - // override next() and handle the custom mode there. - // - virtual token - next (); - - // Peek at the first character of the next token. Return the character - // or '\0' if the next token will be eos. Also return an indicator of - // whether the next token will be separated. - // - pair<char, bool> - peek_char (); - - protected: - struct state - { - lexer_mode mode; - - char sep_pair; - bool sep_space; // Are whitespaces separators (see skip_spaces())? - bool sep_newline; // Is newline special (see skip_spaces())? - bool quotes; // Recognize quoted fragments. - - const char* escapes; // Effective escape sequences to recognize. - - // Word separator characters. For two-character sequence put the first - // one in sep_first and the second one in the corresponding position of - // sep_second. If it's a single-character sequence, then put space in - // sep_second. If there are multiple sequences that start with the same - // character, then repeat the first character in sep_first. - // - const char* sep_first; - const char* sep_second; - }; - - token - next_eval (); - - token - next_quoted (); - - // Lex a word assuming current is the top state (which may already have - // been "expired" from the top). - // - virtual token - word (state current, bool separated); - - // Return true if we have seen any spaces. Skipped empty lines - // don't count. In other words, we are only interested in spaces - // that are on the same line as the following non-space character. - // - bool - skip_spaces (); - - // Diagnostics. - // - protected: - fail_mark fail; - - // Lexer state. - // - protected: - lexer (istream& is, - const path& name, - uint64_t line, - const char* escapes, - bool set_mode) - : char_scanner (is, true /* crlf */, line), - fail ("error", &name_), - name_ (name), - sep_ (false) - { - if (set_mode) - mode (lexer_mode::normal, '@', escapes); - } - - const path name_; - std::stack<state> state_; - - bool sep_; // True if we skipped spaces in peek(). - }; -} - -// Diagnostics plumbing. -// -namespace butl // ADL -{ - inline build2::location - get_location (const butl::char_scanner::xchar& c, const void* data) - { - using namespace build2; - - assert (data != nullptr); // E.g., must be &lexer::name_. - return location (static_cast<const path*> (data), c.line, c.column); - } -} - -#endif // BUILD2_LEXER_HXX |