//===-- lib/Parser/expr-parsers.cpp ---------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// Per-type parsers for expressions.
#include "expr-parsers.h"
#include "basic-parsers.h"
#include "misc-parsers.h"
#include "stmt-parser.h"
#include "token-parsers.h"
#include "type-parser-implementation.h"
#include "flang/Parser/characters.h"
#include "flang/Parser/parse-tree.h"
namespace Fortran::parser {
// R764 boz-literal-constant -> binary-constant | octal-constant | hex-constant
// R765 binary-constant -> B ' digit [digit]... ' | B " digit [digit]... "
// R766 octal-constant -> O ' digit [digit]... ' | O " digit [digit]... "
// R767 hex-constant ->
// Z ' hex-digit [hex-digit]... ' | Z " hex-digit [hex-digit]... "
// extension: X accepted for Z
// extension: BOZX suffix accepted
TYPE_PARSER(construct<BOZLiteralConstant>(BOZLiteral{}))
// R769 array-constructor -> (/ ac-spec /) | lbracket ac-spec rbracket
TYPE_CONTEXT_PARSER("array constructor"_en_US,
construct<ArrayConstructor>(
"(/" >> Parser<AcSpec>{} / "/)" || bracketed(Parser<AcSpec>{})))
// R770 ac-spec -> type-spec :: | [type-spec ::] ac-value-list
TYPE_PARSER(construct<AcSpec>(maybe(typeSpec / "::"),
nonemptyList("expected array constructor values"_err_en_US,
Parser<AcValue>{})) ||
construct<AcSpec>(typeSpec / "::"))
// R773 ac-value -> expr | ac-implied-do
TYPE_PARSER(
// PGI/Intel extension: accept triplets in array constructors
extension<LanguageFeature::TripletInArrayConstructor>(
"nonstandard usage: triplet in array constructor"_port_en_US,
construct<AcValue>(construct<AcValue::Triplet>(scalarIntExpr,
":" >> scalarIntExpr, maybe(":" >> scalarIntExpr)))) ||
construct<AcValue>(indirect(expr)) ||
construct<AcValue>(indirect(Parser<AcImpliedDo>{})))
// R774 ac-implied-do -> ( ac-value-list , ac-implied-do-control )
TYPE_PARSER(parenthesized(
construct<AcImpliedDo>(nonemptyList(Parser<AcValue>{} / lookAhead(","_tok)),
"," >> Parser<AcImpliedDoControl>{})))
// R775 ac-implied-do-control ->
// [integer-type-spec ::] ac-do-variable = scalar-int-expr ,
// scalar-int-expr [, scalar-int-expr]
// R776 ac-do-variable -> do-variable
TYPE_PARSER(construct<AcImpliedDoControl>(
maybe(integerTypeSpec / "::"), loopBounds(scalarIntExpr)))
// R1001 primary ->
// literal-constant | designator | array-constructor |
// structure-constructor | function-reference | type-param-inquiry |
// type-param-name | ( expr )
// type-param-inquiry is parsed as a structure component, except for
// substring%KIND/LEN
constexpr auto primary{instrumented("primary"_en_US,
first(construct<Expr>(indirect(Parser<CharLiteralConstantSubstring>{})),
construct<Expr>(literalConstant),
construct<Expr>(construct<Expr::Parentheses>("(" >>
expr / !","_tok / recovery(")"_tok, SkipPastNested<'(', ')'>{}))),
construct<Expr>(indirect(functionReference) / !"("_tok / !"%"_tok),
construct<Expr>(designator / !"("_tok / !"%"_tok),
construct<Expr>(indirect(Parser<SubstringInquiry>{})), // %LEN or %KIND
construct<Expr>(Parser<StructureConstructor>{}),
construct<Expr>(Parser<ArrayConstructor>{}),
// PGI/XLF extension: COMPLEX constructor (x,y)
construct<Expr>(parenthesized(
construct<Expr::ComplexConstructor>(expr, "," >> expr))),
extension<LanguageFeature::PercentLOC>(
"nonstandard usage: %LOC"_port_en_US,
construct<Expr>("%LOC" >> parenthesized(construct<Expr::PercentLoc>(
indirect(variable)))))))};
// R1002 level-1-expr -> [defined-unary-op] primary
// TODO: Reasonable extension: permit multiple defined-unary-ops
constexpr auto level1Expr{sourced(
primary || // must come before define op to resolve .TRUE._8 ambiguity
construct<Expr>(construct<Expr::DefinedUnary>(definedOpName, primary)))};
// R1004 mult-operand -> level-1-expr [power-op mult-operand]
// R1007 power-op -> **
// Exponentiation (**) is Fortran's only right-associative binary operation.
struct MultOperand {
using resultType = Expr;
constexpr MultOperand() {}
static inline std::optional<Expr> Parse(ParseState &);
};
// Extension: allow + or - before a mult-operand
// Such a unary operand has lower precedence than exponentiation,
// so -x**2 is -(x**2), not (-x)**2; this matches all other
// compilers with this extension.
static constexpr auto standardMultOperand{sourced(MultOperand{})};
static constexpr auto multOperand{standardMultOperand ||
extension<LanguageFeature::SignedMultOperand>(
"nonstandard usage: signed mult-operand"_port_en_US,
construct<Expr>(
construct<Expr::UnaryPlus>("+" >> standardMultOperand))) ||
extension<LanguageFeature::SignedMultOperand>(
"nonstandard usage: signed mult-operand"_port_en_US,
construct<Expr>(construct<Expr::Negate>("-" >> standardMultOperand)))};
inline std::optional<Expr> MultOperand::Parse(ParseState &state) {
std::optional<Expr> result{level1Expr.Parse(state)};
if (result) {
static constexpr auto op{attempt("**"_tok)};
if (op.Parse(state)) {
std::function<Expr(Expr &&)> power{[&result](Expr &&right) {
return Expr{Expr::Power(std::move(result).value(), std::move(right))};
}};
return applyLambda(power, multOperand).Parse(state); // right-recursive
}
}
return result;
}
// R1005 add-operand -> [add-operand mult-op] mult-operand
// R1008 mult-op -> * | /
// The left recursion in the grammar is implemented iteratively.
struct AddOperand {
using resultType = Expr;
constexpr AddOperand() {}
static inline std::optional<Expr> Parse(ParseState &state) {
std::optional<Expr> result{multOperand.Parse(state)};
if (result) {
auto source{result->source};
std::function<Expr(Expr &&)> multiply{[&result](Expr &&right) {
return Expr{
Expr::Multiply(std::move(result).value(), std::move(right))};
}};
std::function<Expr(Expr &&)> divide{[&result](Expr &&right) {
return Expr{Expr::Divide(std::move(result).value(), std::move(right))};
}};
auto more{attempt(sourced("*" >> applyLambda(multiply, multOperand) ||
"/" >> applyLambda(divide, multOperand)))};
while (std::optional<Expr> next{more.Parse(state)}) {
result = std::move(next);
result->source.ExtendToCover(source);
}
}
return result;
}
};
constexpr AddOperand addOperand;
// R1006 level-2-expr -> [[level-2-expr] add-op] add-operand
// R1009 add-op -> + | -
// These are left-recursive productions, implemented iteratively.
// Note that standard Fortran admits a unary + or - to appear only here,
// by means of a missing first operand; e.g., 2*-3 is valid in C but not
// standard Fortran. We accept unary + and - to appear before any primary
// as an extension.
struct Level2Expr {
using resultType = Expr;
constexpr Level2Expr() {}
static inline std::optional<Expr> Parse(ParseState &state) {
static constexpr auto unary{
sourced(
construct<Expr>(construct<Expr::UnaryPlus>("+" >> addOperand)) ||
construct<Expr>(construct<Expr::Negate>("-" >> addOperand))) ||
addOperand};
std::optional<Expr> result{unary.Parse(state)};
if (result) {
auto source{result->source};
std::function<Expr(Expr &&)> add{[&result](Expr &&right) {
return Expr{Expr::Add(std::move(result).value(), std::move(right))};
}};
std::function<Expr(Expr &&)> subtract{[&result](Expr &&right) {
return Expr{
Expr::Subtract(std::move(result).value(), std::move(right))};
}};
auto more{attempt(sourced("+" >> applyLambda(add, addOperand) ||
"-" >> applyLambda(subtract, addOperand)))};
while (std::optional<Expr> next{more.Parse(state)}) {
result = std::move(next);
result->source.ExtendToCover(source);
}
}
return result;
}
};
constexpr Level2Expr level2Expr;
// R1010 level-3-expr -> [level-3-expr concat-op] level-2-expr
// R1011 concat-op -> //
// Concatenation (//) is left-associative for parsing performance, although
// one would never notice if it were right-associated.
struct Level3Expr {
using resultType = Expr;
constexpr Level3Expr() {}
static inline std::optional<Expr> Parse(ParseState &state) {
std::optional<Expr> result{level2Expr.Parse(state)};
if (result) {
auto source{result->source};
std::function<Expr(Expr &&)> concat{[&result](Expr &&right) {
return Expr{Expr::Concat(std::move(result).value(), std::move(right))};
}};
auto more{attempt(sourced("//" >> applyLambda(concat, level2Expr)))};
while (std::optional<Expr> next{more.Parse(state)}) {
result = std::move(next);
result->source.ExtendToCover(source);
}
}
return result;
}
};
constexpr Level3Expr level3Expr;
// R1012 level-4-expr -> [level-3-expr rel-op] level-3-expr
// R1013 rel-op ->
// .EQ. | .NE. | .LT. | .LE. | .GT. | .GE. |
// == | /= | < | <= | > | >= @ | <>
// N.B. relations are not recursive (i.e., LOGICAL is not ordered)
struct Level4Expr {
using resultType = Expr;
constexpr Level4Expr() {}
static inline std::optional<Expr> Parse(ParseState &state) {
std::optional<Expr> result{level3Expr.Parse(state)};
if (result) {
auto source{result->source};
std::function<Expr(Expr &&)> lt{[&result](Expr &&right) {
return Expr{Expr::LT(std::move(result).value(), std::move(right))};
}};
std::function<Expr(Expr &&)> le{[&result](Expr &&right) {
return Expr{Expr::LE(std::move(result).value(), std::move(right))};
}};
std::function<Expr(Expr &&)> eq{[&result](Expr &&right) {
return Expr{Expr::EQ(std::move(result).value(), std::move(right))};
}};
std::function<Expr(Expr &&)> ne{[&result](Expr &&right) {
return Expr{Expr::NE(std::move(result).value(), std::move(right))};
}};
std::function<Expr(Expr &&)> ge{[&result](Expr &&right) {
return Expr{Expr::GE(std::move(result).value(), std::move(right))};
}};
std::function<Expr(Expr &&)> gt{[&result](Expr &&right) {
return Expr{Expr::GT(std::move(result).value(), std::move(right))};
}};
auto more{attempt(
sourced((".LT."_tok || "<"_tok) >> applyLambda(lt, level3Expr) ||
(".LE."_tok || "<="_tok) >> applyLambda(le, level3Expr) ||
(".EQ."_tok || "=="_tok) >> applyLambda(eq, level3Expr) ||
(".NE."_tok || "/="_tok ||
extension<LanguageFeature::AlternativeNE>(
"nonstandard usage: <> for /= or .NE."_port_en_US,
"<>"_tok /* PGI/Cray extension; Cray also has .LG. */)) >>
applyLambda(ne, level3Expr) ||
(".GE."_tok || ">="_tok) >> applyLambda(ge, level3Expr) ||
(".GT."_tok || ">"_tok) >> applyLambda(gt, level3Expr)))};
if (std::optional<Expr> next{more.Parse(state)}) {
next->source.ExtendToCover(source);
return next;
}
}
return result;
}
};
constexpr Level4Expr level4Expr;
// R1014 and-operand -> [not-op] level-4-expr
// R1018 not-op -> .NOT.
// N.B. Fortran's .NOT. binds less tightly than its comparison operators do.
// PGI/Intel extension: accept multiple .NOT. operators
struct AndOperand {
using resultType = Expr;
constexpr AndOperand() {}
static inline std::optional<Expr> Parse(ParseState &);
};
constexpr AndOperand andOperand;
// Match a logical operator or, optionally, its abbreviation.
inline constexpr auto logicalOp(const char *op, const char *abbrev) {
return TokenStringMatch{op} ||
extension<LanguageFeature::LogicalAbbreviations>(
"nonstandard usage: abbreviated LOGICAL operator"_port_en_US,
TokenStringMatch{abbrev});
}
inline std::optional<Expr> AndOperand::Parse(ParseState &state) {
static constexpr auto notOp{attempt(logicalOp(".NOT.", ".N.") >> andOperand)};
if (std::optional<Expr> negation{notOp.Parse(state)}) {
return Expr{Expr::NOT{std::move(*negation)}};
} else {
return level4Expr.Parse(state);
}
}
// R1015 or-operand -> [or-operand and-op] and-operand
// R1019 and-op -> .AND.
// .AND. is left-associative
struct OrOperand {
using resultType = Expr;
constexpr OrOperand() {}
static inline std::optional<Expr> Parse(ParseState &state) {
static constexpr auto operand{sourced(andOperand)};
std::optional<Expr> result{operand.Parse(state)};
if (result) {
auto source{result->source};
std::function<Expr(Expr &&)> logicalAnd{[&result](Expr &&right) {
return Expr{Expr::AND(std::move(result).value(), std::move(right))};
}};
auto more{attempt(sourced(
logicalOp(".AND.", ".A.") >> applyLambda(logicalAnd, andOperand)))};
while (std::optional<Expr> next{more.Parse(state)}) {
result = std::move(next);
result->source.ExtendToCover(source);
}
}
return result;
}
};
constexpr OrOperand orOperand;
// R1016 equiv-operand -> [equiv-operand or-op] or-operand
// R1020 or-op -> .OR.
// .OR. is left-associative
struct EquivOperand {
using resultType = Expr;
constexpr EquivOperand() {}
static inline std::optional<Expr> Parse(ParseState &state) {
std::optional<Expr> result{orOperand.Parse(state)};
if (result) {
auto source{result->source};
std::function<Expr(Expr &&)> logicalOr{[&result](Expr &&right) {
return Expr{Expr::OR(std::move(result).value(), std::move(right))};
}};
auto more{attempt(sourced(
logicalOp(".OR.", ".O.") >> applyLambda(logicalOr, orOperand)))};
while (std::optional<Expr> next{more.Parse(state)}) {
result = std::move(next);
result->source.ExtendToCover(source);
}
}
return result;
}
};
constexpr EquivOperand equivOperand;
// R1017 level-5-expr -> [level-5-expr equiv-op] equiv-operand
// R1021 equiv-op -> .EQV. | .NEQV.
// Logical equivalence is left-associative.
// Extension: .XOR. as synonym for .NEQV.
struct Level5Expr {
using resultType = Expr;
constexpr Level5Expr() {}
static inline std::optional<Expr> Parse(ParseState &state) {
std::optional<Expr> result{equivOperand.Parse(state)};
if (result) {
auto source{result->source};
std::function<Expr(Expr &&)> eqv{[&result](Expr &&right) {
return Expr{Expr::EQV(std::move(result).value(), std::move(right))};
}};
std::function<Expr(Expr &&)> neqv{[&result](Expr &&right) {
return Expr{Expr::NEQV(std::move(result).value(), std::move(right))};
}};
auto more{attempt(sourced(".EQV." >> applyLambda(eqv, equivOperand) ||
(".NEQV."_tok ||
extension<LanguageFeature::XOROperator>(
"nonstandard usage: .XOR./.X. spelling of .NEQV."_port_en_US,
logicalOp(".XOR.", ".X."))) >>
applyLambda(neqv, equivOperand)))};
while (std::optional<Expr> next{more.Parse(state)}) {
result = std::move(next);
result->source.ExtendToCover(source);
}
}
return result;
}
};
constexpr Level5Expr level5Expr;
// R1022 expr -> [expr defined-binary-op] level-5-expr
// Defined binary operators associate leftwards.
template <> std::optional<Expr> Parser<Expr>::Parse(ParseState &state) {
std::optional<Expr> result{level5Expr.Parse(state)};
if (result) {
auto source{result->source};
std::function<Expr(DefinedOpName &&, Expr &&)> defBinOp{
[&result](DefinedOpName &&op, Expr &&right) {
return Expr{Expr::DefinedBinary(
std::move(op), std::move(result).value(), std::move(right))};
}};
auto more{attempt(
sourced(applyLambda<Expr>(defBinOp, definedOpName, level5Expr)))};
while (std::optional<Expr> next{more.Parse(state)}) {
result = std::move(next);
result->source.ExtendToCover(source);
}
}
return result;
}
// R1003 defined-unary-op -> . letter [letter]... .
// R1023 defined-binary-op -> . letter [letter]... .
// R1414 local-defined-operator -> defined-unary-op | defined-binary-op
// R1415 use-defined-operator -> defined-unary-op | defined-binary-op
// C1003 A defined operator must be distinct from logical literal constants
// and intrinsic operator names; this is handled by attempting their parses
// first, and by name resolution on their definitions, for best errors.
// N.B. The name of the operator is captured with the dots around it.
constexpr auto definedOpNameChar{letter ||
extension<LanguageFeature::PunctuationInNames>(
"nonstandard usage: non-alphabetic character in defined operator"_port_en_US,
"$@"_ch)};
TYPE_PARSER(
space >> construct<DefinedOpName>(sourced("."_ch >>
some(definedOpNameChar) >> construct<Name>() / "."_ch)))
// R1028 specification-expr -> scalar-int-expr
TYPE_PARSER(construct<SpecificationExpr>(scalarIntExpr))
// R1032 assignment-stmt -> variable = expr
TYPE_CONTEXT_PARSER("assignment statement"_en_US,
construct<AssignmentStmt>(variable / "=", expr))
// R1033 pointer-assignment-stmt ->
// data-pointer-object [( bounds-spec-list )] => data-target |
// data-pointer-object ( bounds-remapping-list ) => data-target |
// proc-pointer-object => proc-target
// R1034 data-pointer-object ->
// variable-name | scalar-variable % data-pointer-component-name
// C1022 a scalar-variable shall be a data-ref
// C1024 a data-pointer-object shall not be a coindexed object
// R1038 proc-pointer-object -> proc-pointer-name | proc-component-ref
//
// A distinction can't be made at the time of the initial parse between
// data-pointer-object and proc-pointer-object, or between data-target
// and proc-target.
TYPE_CONTEXT_PARSER("pointer assignment statement"_en_US,
construct<PointerAssignmentStmt>(dataRef,
parenthesized(nonemptyList(Parser<BoundsRemapping>{})), "=>" >> expr) ||
construct<PointerAssignmentStmt>(dataRef,
defaulted(parenthesized(nonemptyList(Parser<BoundsSpec>{}))),
"=>" >> expr))
// R1035 bounds-spec -> lower-bound-expr :
TYPE_PARSER(construct<BoundsSpec>(boundExpr / ":"))
// R1036 bounds-remapping -> lower-bound-expr : upper-bound-expr
TYPE_PARSER(construct<BoundsRemapping>(boundExpr / ":", boundExpr))
// R1039 proc-component-ref -> scalar-variable % procedure-component-name
// C1027 the scalar-variable must be a data-ref without coindices.
TYPE_PARSER(construct<ProcComponentRef>(structureComponent))
// R1041 where-stmt -> WHERE ( mask-expr ) where-assignment-stmt
// R1045 where-assignment-stmt -> assignment-stmt
// R1046 mask-expr -> logical-expr
TYPE_CONTEXT_PARSER("WHERE statement"_en_US,
construct<WhereStmt>("WHERE" >> parenthesized(logicalExpr), assignmentStmt))
// R1042 where-construct ->
// where-construct-stmt [where-body-construct]...
// [masked-elsewhere-stmt [where-body-construct]...]...
// [elsewhere-stmt [where-body-construct]...] end-where-stmt
TYPE_CONTEXT_PARSER("WHERE construct"_en_US,
construct<WhereConstruct>(statement(Parser<WhereConstructStmt>{}),
many(whereBodyConstruct),
many(construct<WhereConstruct::MaskedElsewhere>(
statement(Parser<MaskedElsewhereStmt>{}),
many(whereBodyConstruct))),
maybe(construct<WhereConstruct::Elsewhere>(
statement(Parser<ElsewhereStmt>{}), many(whereBodyConstruct))),
statement(Parser<EndWhereStmt>{})))
// R1043 where-construct-stmt -> [where-construct-name :] WHERE ( mask-expr )
TYPE_CONTEXT_PARSER("WHERE construct statement"_en_US,
construct<WhereConstructStmt>(
maybe(name / ":"), "WHERE" >> parenthesized(logicalExpr)))
// R1044 where-body-construct ->
// where-assignment-stmt | where-stmt | where-construct
TYPE_PARSER(construct<WhereBodyConstruct>(statement(assignmentStmt)) ||
construct<WhereBodyConstruct>(statement(whereStmt)) ||
construct<WhereBodyConstruct>(indirect(whereConstruct)))
// R1047 masked-elsewhere-stmt ->
// ELSEWHERE ( mask-expr ) [where-construct-name]
TYPE_CONTEXT_PARSER("masked ELSEWHERE statement"_en_US,
construct<MaskedElsewhereStmt>(
"ELSE WHERE" >> parenthesized(logicalExpr), maybe(name)))
// R1048 elsewhere-stmt -> ELSEWHERE [where-construct-name]
TYPE_CONTEXT_PARSER("ELSEWHERE statement"_en_US,
construct<ElsewhereStmt>("ELSE WHERE" >> maybe(name)))
// R1049 end-where-stmt -> ENDWHERE [where-construct-name]
TYPE_CONTEXT_PARSER("END WHERE statement"_en_US,
construct<EndWhereStmt>(recovery(
"END WHERE" >> maybe(name), namedConstructEndStmtErrorRecovery)))
// R1050 forall-construct ->
// forall-construct-stmt [forall-body-construct]... end-forall-stmt
TYPE_CONTEXT_PARSER("FORALL construct"_en_US,
construct<ForallConstruct>(statement(Parser<ForallConstructStmt>{}),
many(Parser<ForallBodyConstruct>{}),
statement(Parser<EndForallStmt>{})))
// R1051 forall-construct-stmt ->
// [forall-construct-name :] FORALL concurrent-header
TYPE_CONTEXT_PARSER("FORALL construct statement"_en_US,
construct<ForallConstructStmt>(
maybe(name / ":"), "FORALL" >> indirect(concurrentHeader)))
// R1052 forall-body-construct ->
// forall-assignment-stmt | where-stmt | where-construct |
// forall-construct | forall-stmt
TYPE_PARSER(construct<ForallBodyConstruct>(statement(forallAssignmentStmt)) ||
construct<ForallBodyConstruct>(statement(whereStmt)) ||
construct<ForallBodyConstruct>(whereConstruct) ||
construct<ForallBodyConstruct>(indirect(forallConstruct)) ||
construct<ForallBodyConstruct>(statement(forallStmt)))
// R1053 forall-assignment-stmt -> assignment-stmt | pointer-assignment-stmt
TYPE_PARSER(construct<ForallAssignmentStmt>(assignmentStmt) ||
construct<ForallAssignmentStmt>(pointerAssignmentStmt))
// R1054 end-forall-stmt -> END FORALL [forall-construct-name]
TYPE_CONTEXT_PARSER("END FORALL statement"_en_US,
construct<EndForallStmt>(recovery(
"END FORALL" >> maybe(name), namedConstructEndStmtErrorRecovery)))
// R1055 forall-stmt -> FORALL concurrent-header forall-assignment-stmt
TYPE_CONTEXT_PARSER("FORALL statement"_en_US,
construct<ForallStmt>("FORALL" >> indirect(concurrentHeader),
unlabeledStatement(forallAssignmentStmt)))
} // namespace Fortran::parser
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