forked from OSchip/llvm-project
101 lines
4.1 KiB
C++
101 lines
4.1 KiB
C++
//===-- lib/Parser/stmt-parser.h --------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef FORTRAN_PARSER_STMT_PARSER_H_
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#define FORTRAN_PARSER_STMT_PARSER_H_
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// Basic parsing of statements.
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#include "basic-parsers.h"
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#include "token-parsers.h"
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namespace Fortran::parser {
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// statement(p) parses Statement<P> for some statement type P that is the
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// result type of the argument parser p, while also handling labels and
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// end-of-statement markers.
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// R611 label -> digit [digit]...
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constexpr auto label{space >> digitString64 / spaceCheck};
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template <typename PA>
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inline constexpr auto unterminatedStatement(const PA &p) {
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return skipStuffBeforeStatement >>
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sourced(construct<Statement<typename PA::resultType>>(
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maybe(label), space >> p));
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}
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constexpr auto endOfLine{
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"\n"_ch >> ok || fail("expected end of line"_err_en_US)};
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constexpr auto semicolons{";"_ch >> skipMany(";"_tok) / space / maybe("\n"_ch)};
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constexpr auto endOfStmt{
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space >> withMessage("expected end of statement"_err_en_US,
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semicolons || endOfLine)};
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constexpr auto forceEndOfStmt{recovery(endOfStmt, SkipPast<'\n'>{})};
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template <typename PA> inline constexpr auto statement(const PA &p) {
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return unterminatedStatement(p) / endOfStmt;
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}
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// unlabeledStatement() is basically statement() for those few situations
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// in Fortran where a statement cannot have a label.
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template <typename PA> inline constexpr auto unlabeledStatement(const PA &p) {
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return space >>
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sourced(construct<UnlabeledStatement<typename PA::resultType>>(p));
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}
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// This unambiguousStatement() variant of statement() provides better error
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// recovery for contexts containing statements that might have trailing
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// garbage, but it must be used only when no instance of the statement in
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// question could also be a legal prefix of some other statement that might
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// be valid at that point. It only makes sense to use this within "some()"
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// or "many()" so as to not end the list of statements.
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template <typename PA> inline constexpr auto unambiguousStatement(const PA &p) {
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return unterminatedStatement(p) / forceEndOfStmt;
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}
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constexpr auto ignoredStatementPrefix{
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skipStuffBeforeStatement >> maybe(label) >> maybe(name / ":") >> space};
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// Error recovery within a statement() call: skip *to* the end of the line,
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// unless at an END or CONTAINS statement.
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constexpr auto inStmtErrorRecovery{!"END"_tok >> !"CONTAINS"_tok >>
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SkipTo<'\n'>{} >> construct<ErrorRecovery>()};
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// Error recovery within statement sequences: skip *past* the end of the line,
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// but not over an END or CONTAINS statement.
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constexpr auto skipStmtErrorRecovery{!"END"_tok >> !"CONTAINS"_tok >>
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SkipPast<'\n'>{} >> construct<ErrorRecovery>()};
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// Error recovery across statements: skip the line, unless it looks
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// like it might end the containing construct.
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constexpr auto stmtErrorRecoveryStart{ignoredStatementPrefix};
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constexpr auto skipBadLine{SkipPast<'\n'>{} >> construct<ErrorRecovery>()};
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constexpr auto executionPartErrorRecovery{stmtErrorRecoveryStart >>
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!"END"_tok >> !"CONTAINS"_tok >> !"ELSE"_tok >> !"CASE"_tok >>
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!"TYPE IS"_tok >> !"CLASS"_tok >> !"RANK"_tok >>
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!("!$OMP "_sptok >> ("END"_tok || "SECTION"_id)) >> skipBadLine};
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// END statement error recovery
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constexpr auto missingOptionalName{defaulted(cut >> maybe(name))};
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constexpr auto noNameEnd{"END" >> missingOptionalName};
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constexpr auto atEndOfStmt{space >>
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withMessage("expected end of statement"_err_en_US, lookAhead(";\n"_ch))};
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constexpr auto bareEnd{noNameEnd / recovery(atEndOfStmt, SkipTo<'\n'>{})};
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constexpr auto endStmtErrorRecovery{
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("END"_tok >> SkipTo<'\n'>{} || ok) >> missingOptionalName};
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constexpr auto progUnitEndStmtErrorRecovery{
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(many(!"END"_tok >> SkipPast<'\n'>{}) >>
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("END"_tok >> SkipTo<'\n'>{} || consumedAllInput)) >>
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missingOptionalName};
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} // namespace Fortran::parser
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#endif // FORTRAN_PARSER_STMT_PARSER_H_
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