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carbon-lang/executable_semantics/syntax/parser.ypp
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Dave Abrahams 436a9dda79 [executable semantics] Minimal cxx parser (#363)
Makes a minimal transition to using C++ in the parser.
2021-03-09 20:46:52 -08:00

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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// -----------------------------------------------------------------------------
// Bison Configuration
// -----------------------------------------------------------------------------
%require "3.2"
%language "c++"
// We don't need a separate header for Bison locations yet.
%define api.location.file none
//
// Parameters to the parser and lexer
//
// Parameters to the parser are stored therein as protected data members, and
// thus available to its methods.
// "out" parameter passed to the parser, where the AST is written.
%parse-param {std::optional<Carbon::AST>& parsedProgram}
// "inout" parameter passed to both the parser and the lexer.
%param {Carbon::ParseAndLexContext& context}
// -----------------------------------------------------------------------------
%code top {
#include <algorithm>
#include <cstdarg>
#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <list>
#include "executable_semantics/syntax/syntax_helpers.h"
#include "executable_semantics/syntax/parse_and_lex_context.h"
}
%code requires {
#include <optional>
#include "executable_semantics/ast/abstract_syntax_tree.h"
#include "executable_semantics/ast/declaration.h"
#include "executable_semantics/ast/field_list.h"
#include "executable_semantics/ast/function_definition.h"
namespace Carbon {
class ParseAndLexContext;
}
}
%code {
extern int yylineno;
void yy::parser::error(
const location_type&, const std::string& message)
{
context.PrintDiagnostic(message, yylineno);
}
}
%define api.value.type union
%token <int> integer_literal
%token <char*> identifier
%type <char*> designator
%type <Carbon::Declaration*> declaration
%type <Carbon::FunctionDefinition*> function_declaration
%type <Carbon::FunctionDefinition*> function_definition
%type <std::list<Carbon::Declaration>*> declaration_list
%type <Carbon::Statement*> statement
%type <Carbon::Statement*> optional_else
%type <Carbon::Statement*> statement_list
%type <Carbon::Expression*> expression
%type <Carbon::Expression*> pattern
%type <Carbon::Expression*> return_type
%type <Carbon::Expression*> paren_expression
%type <Carbon::Expression*> tuple
%type <Carbon::Member*> member
%type <std::list<Carbon::Member*>*> member_list
%type <Carbon::FieldList*> field
%type <Carbon::FieldList*> field_list
%type <std::pair<std::string, Carbon::Expression*>*> alternative
%type <std::list<std::pair<std::string, Carbon::Expression*>>*> alternative_list
%type <std::pair<Carbon::Expression*, Carbon::Statement*>*> clause
%type <std::list<std::pair<Carbon::Expression*, Carbon::Statement*>>*> clause_list
%token AND
%token OR
%token NOT
%token INT
%token BOOL
%token TYPE
%token FN
%token FNTY
%token ARROW
%token VAR
%token EQUAL
%token IF
%token ELSE
%token WHILE
%token BREAK
%token CONTINUE
%token RETURN
%token TRUE
%token FALSE
%token STRUCT
%token CHOICE
%token MATCH
%token CASE
%token DBLARROW
%token DEFAULT
%token AUTO
%nonassoc '{' '}'
%nonassoc ':' ',' DBLARROW
%left OR AND
%nonassoc EQUAL NOT
%left '+' '-'
%left '.' ARROW
%nonassoc '(' ')' '[' ']'
%start input
%locations
%%
input: declaration_list
{ parsedProgram = $1; }
;
pattern:
expression
{ $$ = $1; }
;
expression:
identifier
{ $$ = Carbon::MakeVar(yylineno, $1); }
| expression designator
{ $$ = Carbon::MakeGetField(yylineno, $1, $2); }
| expression '[' expression ']'
{ $$ = Carbon::MakeIndex(yylineno, $1, $3); }
| expression ':' identifier
{ $$ = Carbon::MakeVarPat(yylineno, $3, $1); }
| integer_literal
{ $$ = Carbon::MakeInt(yylineno, $1); }
| TRUE
{ $$ = Carbon::MakeBool(yylineno, true); }
| FALSE
{ $$ = Carbon::MakeBool(yylineno, false); }
| INT
{ $$ = Carbon::MakeIntType(yylineno); }
| BOOL
{ $$ = Carbon::MakeBoolType(yylineno); }
| TYPE
{ $$ = Carbon::MakeTypeType(yylineno); }
| AUTO
{ $$ = Carbon::MakeAutoType(yylineno); }
| paren_expression { $$ = $1; }
| expression EQUAL expression
{ $$ = Carbon::MakeBinOp(yylineno, Carbon::Operator::Eq, $1, $3); }
| expression '+' expression
{ $$ = Carbon::MakeBinOp(yylineno, Carbon::Operator::Add, $1, $3); }
| expression '-' expression
{ $$ = Carbon::MakeBinOp(yylineno, Carbon::Operator::Sub, $1, $3); }
| expression AND expression
{ $$ = Carbon::MakeBinOp(yylineno, Carbon::Operator::And, $1, $3); }
| expression OR expression
{ $$ = Carbon::MakeBinOp(yylineno, Carbon::Operator::Or, $1, $3); }
| NOT expression
{ $$ = Carbon::MakeUnOp(yylineno, Carbon::Operator::Not, $2); }
| '-' expression
{ $$ = Carbon::MakeUnOp(yylineno, Carbon::Operator::Neg, $2); }
| expression tuple
{ $$ = Carbon::MakeCall(yylineno, $1, $2); }
| FNTY tuple return_type
{ $$ = Carbon::MakeFunType(yylineno, $2, $3); }
;
designator: '.' identifier { $$ = $2; }
;
paren_expression: '(' field_list ')'
{
if ($2->fields->size() == 1 &&
$2->fields->front().first == "" &&
!$2->has_explicit_comma) {
$$ = $2->fields->front().second;
} else {
auto vec = new std::vector<std::pair<std::string,Carbon::Expression*>>(
$2->fields->begin(), $2->fields->end());
$$ = Carbon::MakeTuple(yylineno, vec);
}
}
;
tuple: '(' field_list ')'
{
auto vec = new std::vector<std::pair<std::string,Carbon::Expression*>>(
$2->fields->begin(), $2->fields->end());
$$ = Carbon::MakeTuple(yylineno, vec);
}
field:
pattern
{
auto fields =
new std::list<std::pair<std::string, Carbon::Expression*>>();
fields->push_back(std::make_pair("", $1));
$$ = Carbon::MakeFieldList(fields);
}
| designator '=' pattern
{
auto fields =
new std::list<std::pair<std::string, Carbon::Expression*>>();
fields->push_back(std::make_pair($1, $3));
$$ = Carbon::MakeFieldList(fields);
}
;
field_list:
// Empty
{
$$ = Carbon::MakeFieldList(
new std::list<std::pair<std::string, Carbon::Expression*>>());
}
| field
{ $$ = $1; }
| field ',' field_list
{ $$ = Carbon::MakeConsField($1, $3); }
;
clause:
CASE pattern DBLARROW statement
{ $$ = new std::pair<Carbon::Expression*, Carbon::Statement*>($2, $4); }
| DEFAULT DBLARROW statement
{
auto vp = Carbon::MakeVarPat(yylineno, "_",
Carbon::MakeAutoType(yylineno));
$$ = new std::pair<Carbon::Expression*, Carbon::Statement*>(vp, $3);
}
;
clause_list:
// Empty
{
$$ = new std::list<std::pair<Carbon::Expression*, Carbon::Statement*>>();
}
| clause clause_list
{ $$ = $2; $$->push_front(*$1); }
;
statement:
expression '=' expression ';'
{ $$ = Carbon::MakeAssign(yylineno, $1, $3); }
| VAR pattern '=' expression ';'
{ $$ = Carbon::MakeVarDef(yylineno, $2, $4); }
| expression ';'
{ $$ = Carbon::MakeExpStmt(yylineno, $1); }
| IF '(' expression ')' statement optional_else
{ $$ = Carbon::MakeIf(yylineno, $3, $5, $6); }
| WHILE '(' expression ')' statement
{ $$ = Carbon::MakeWhile(yylineno, $3, $5); }
| BREAK ';'
{ $$ = Carbon::MakeBreak(yylineno); }
| CONTINUE ';'
{ $$ = Carbon::MakeContinue(yylineno); }
| RETURN expression ';'
{ $$ = Carbon::MakeReturn(yylineno, $2); }
| '{' statement_list '}'
{ $$ = Carbon::MakeBlock(yylineno, $2); }
| MATCH '(' expression ')' '{' clause_list '}'
{ $$ = Carbon::MakeMatch(yylineno, $3, $6); }
;
optional_else:
// Empty
{ $$ = 0; }
| ELSE statement { $$ = $2; }
;
statement_list:
// Empty
{ $$ = 0; }
| statement statement_list
{ $$ = Carbon::MakeSeq(yylineno, $1, $2); }
;
return_type:
// Empty
{
$$ = Carbon::MakeTuple(
yylineno,
new std::vector<std::pair<std::string, Carbon::Expression*>>());
}
| ARROW expression
{ $$ = $2; }
;
function_definition:
FN identifier tuple return_type '{' statement_list '}'
{ $$ = MakeFunDef(yylineno, $2, $4, $3, $6); }
| FN identifier tuple DBLARROW expression ';'
{
$$ = Carbon::MakeFunDef(yylineno, $2, Carbon::MakeAutoType(yylineno), $3,
Carbon::MakeReturn(yylineno, $5));
}
;
function_declaration:
FN identifier tuple return_type ';'
{ $$ = MakeFunDef(yylineno, $2, $4, $3, 0); }
;
member:
VAR expression ':' identifier ';'
{ $$ = MakeField(yylineno, $4, $2); }
;
member_list:
// Empty
{ $$ = new std::list<Carbon::Member*>(); }
| member member_list
{ $$ = $2; $$->push_front($1); }
;
alternative:
identifier tuple
{ $$ = new std::pair<std::string, Carbon::Expression*>($1, $2); }
| identifier
{
$$ = new std::pair<std::string, Carbon::Expression*>(
$1, Carbon::MakeTuple(
yylineno,
new std::vector<std::pair<std::string, Carbon::Expression*>>()));
}
;
alternative_list:
// Empty
{ $$ = new std::list<std::pair<std::string, Carbon::Expression*>>(); }
| alternative
{
$$ = new std::list<std::pair<std::string, Carbon::Expression*>>();
$$->push_front(*$1);
}
| alternative ',' alternative_list
{ $$ = $3; $$->push_front(*$1); }
;
declaration:
function_definition
{ $$ = new Carbon::Declaration(Carbon::FunctionDeclaration{$1}); }
| function_declaration
{ $$ = new Carbon::Declaration(Carbon::FunctionDeclaration{$1}); }
| STRUCT identifier '{' member_list '}'
{
$$ = new Carbon::Declaration(
Carbon::StructDeclaration{yylineno, $2, $4});
}
| CHOICE identifier '{' alternative_list '}'
{
$$ = new Carbon::Declaration(
Carbon::ChoiceDeclaration{yylineno, $2, std::list(*$4)});
}
;
declaration_list:
// Empty
{ $$ = new std::list<Carbon::Declaration>(); }
| declaration declaration_list
{
$$ = $2;
$$->push_front(*$1);
}
;
%%