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m2r10-grammar.gll
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m2r10-grammar.gll
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/* M2R10 -- EBNF Grammar for Modula-2 Revision 2010, status Nov 15, 2016.
*
* Copyright (c) 2016 The Modula-2 Software Foundation
*
* Author & Maintainer: Benjamin Kowarsch <org.m2sf>
*
* @synopsis
*
* Modula-2 R10 is a modern revision of Modula-2 by B.Kowarsch and R.Sutcliffe
* specified in "Modula-2 Revision 2010".
*
* This document describes the grammar of Modula-2 R10 in EBNF.
*
* @repository
*
* https://github.com/m2sf/m2r10
*
* @file
*
* m2r10-grammar.gll
*
* Grammar of Modula-2 R10 source files.
*
*/
grammar Modula2;
/* * * R e s e r v e d W o r d s * * */
reserved
ALIAS, AND, ARGLIST, ARRAY, BARE, BEGIN, BLUEPRINT, BY, CASE, CONST,
DEFINITION, DIV, DO, ELSE, ELSIF, END, EXIT, FOR, FROM, GENLIB, IF,
IMPLEMENTATION, IMPORT, IN, LOOP, MOD, MODULE, NEW, NONE, NOT, OF, OPAQUE,
OR, POINTER, PROCEDURE, RECORD, REFERENTIAL, RELEASE, REPEAT, RETAIN,
RETURN, SET, THEN, TO, TYPE, UNTIL, VAR, WHILE, YIELD;
/* * * N o n - T e r m i n a l S y m b o l s * * */
/* Compilation Unit */
compilationUnit :=
definitionModule | implOrPrgmModule | blueprint
;
/*** Definition Module Syntax ***/
/* Definition Module */
definitionModule :=
DEFINITION MODULE moduleIdent
( '[' blueprintToObey ']' )? ( FOR typeToExtend )? ';'
import* definition* END moduleIdent '.'
;
/* Module Identifier */
alias moduleIdent = StdIdent ;
/* Type To Extend */
alias typeToExtend = StdIdent ;
/* Blueprint Identifier */
alias blueprintIdent = StdIdent ;
/* Blueprint To Obey */
alias blueprintToObey = blueprintIdent ;
/* Import */
import :=
( IMPORT impexLib ( ',' impexLib )* | libGenDirective ) ';'
;
/* Import/Re-Export Library */
impexLib :=
libIdent reExport?
;
/* Library Identifier */
alias libIdent = StdIdent ;
/* Re-Export Tag */
alias reExport := '+' ;
/* Library Generation Directive */
libGenDirective :=
GENLIB libIdent FROM template FOR substitutionList END
;
/* Substitution List */
substitutionList :=
substitution ( ';' substitution )*
;
/* Substitution */
substitution :=
placeholder '=' replacement
;
/* Template */
alias template = StdIdent ;
/* Placeholder */
alias placeholder = StdIdent ;
/* Replacement */
replacement :=
NumberLiteral | StringLiteral | ChevronText
;
/* Identifier */
ident :=
StdIdent | ForeignIdent
;
/* Qualified Identifier */
qualident :=
Ident ( '.' Ident )*
;
/* Identifier List */
identList :=
Ident ( ',' Ident )*
;
/* Definition */
definition :=
CONST ( constDefinition ';' )+ |
TYPE ( typeDefinition ';' )+ |
VAR ( identList ':' typeIdent ';' )+ |
procedureHeader ';' |
toDoList ';'
;
/* Constant Definition */
constDefinition :=
constDefProlog? Ident '=' constExpression
;
/* Constant Definition Prolog */
constDefProlog :=
'[' propertyToBindTo ']' | restrictedExport
;
/* Constant Expression */
alias constExpression = expression ;
/* restricted Export */
alias restrictedExport = '*' ;
/* Type Definition */
typeDefinition :=
restrictedExport? Ident '=' ( OPAQUE | type )
;
/* Type */
type :=
aliasType | derivedType | immutableType | subrangeType | enumType |
setType | arrayType | recordType | pointerType | coroutineType |
procedureType
;
/* Alias Type */
aliasType :=
ALIAS OF typeIdent
;
/* Type Identifier */
alias typeIdent = qualident ;
/* Derived Type */
alias derivedType = typeIdent ;
/* Immutable Type */
immutableType :=
CONST typeIdent
;
/* Subrange Type */
subrangeType :=
range OF ordinalOrScalarType
;
/* Range */
range :=
'[' lowerBound '..' upperBound ']'
;
/* Lower Bound */
lowerBound :=
greaterThan? constExpression
;
/* Greater Than */
alias greaterThan = '>' ;
/* Upper Bound */
upperBound :=
'..' lessThan? constExpression
;
/* Less Than */
alias lessThan = '<' ;
/* Ordinal Or Scalar Type */
alias ordinalOrScalarType = typeIdent ;
/* Enumeration Type */
enumType :=
'(' ( '+' enumTypeToExtend ',' )? identList ')'
;
/* Enumeration Type To Extend */
alias enumTypeToExtend = enumTypeIdent ;
/* Enumeration Type Identifier */
alias enumTypeIdent = typeIdent ;
/* Set Type */
setType :=
SET OF enumTypeIdent
;
/* Array Type */
arrayType :=
BARE? ARRAY valueCount ( ',' valueCount )* OF typeIdent
;
/* Value Count */
alias valueCount = constExpression ;
/* Record Type */
recordType :=
RECORD ( '(' recTypeToExtend ')' )?
fieldList ( ';' fieldList )* END
;
/* Record Type To Extend */
recTypeToExtend :=
typeIdent | NIL
;
/* Field List */
fieldList :=
restrictedExport? varOrFieldDeclaration ( '=' constExpression )?
;
/* Pointer Type */
pointerType :=
POINTER TO typeIdent
;
/* Coroutine Type */
COROUTINE '(' assocProcType ')'
;
/* Associated Procedure Type */
alias assocProcType = typeIdent ;
/* Procedure Type */
procedureType :=
PROCEDURE ( '(' formalType ( ',' formalType )* ')' )? ( ':' returnedType )?
;
/* Formal Type */
formalType :=
nonAttrFormalType | attributedFormalType |
allocatingFormalType | variadicFormalType
;
/* Returned Type */
alias returnedType = typeIdent ;
/* Non-Attributed Formal Type */
nonAttrFormalType :=
( BARE? ARRAY identList? OF )? typeIdent | castingFormalType
;
/* Casting Formal Type */
castingFormalType :=
CAST ( BARE ARRAY OF OCTET | addressTypeIdent )
;
/* Address Type Ident */
addressTypeIdent :=
( UNSAFE '.' )? ADDRESS
;
/* Attributed Formal Type */
attributedFormalType :=
( CONST | VAR ) ( nonAttrFormalType | simpleVariadicFormalType )
;
/* Allocating Formal Type */
allocatingFormalType :=
NEW ( pointerTypeIdent | CAST addressTypeIdent )
;
/* Pointer Type Identifier */
alias pointerTypeIdent = typeIdent ;
/* Simple Variadic Formal Type */
simpleVariadicFormalType :=
ARGLIST reqNumOrArgs? OF nonAttrFormalType
;
/* Required Number Of Arguments */
reqNumOrArgs :=
greaterThan? constExpression
;
/* Variadic Formal Type */
variadicFormalType :=
ARGLIST reqNumOfArgs? OF variadicTypeDescriptor
;
/* Variadic Type Descriptor */
variadicTypeDescriptor :=
'{' variadicTypeComponent ( ',' variadicTypeComponent )* '}' |
nonAttrFormalType
;
/* Variadic Type Component */
variadicTypeComponent :=
( CONST | VAR )? nonAttrFormalType
;
/* Procedure Header */
procedureHeader :=
PROCEDURE procHeaderProlog? procedureSignature defaultArg?
;
/* Procedure Header Prolog */
procHeaderProlog :=
'[' ( entityToBindTo | COROUTINE ) ']' | restrictedExport
;
/* Default Argument */
defaultArg :=
Ident '=' constExprOrConstArgFuncCall
;
/* Constant Expression Or Constant Argument Function Call */
alias constExprOrConstArgFuncCall = expression ;
/* PROCEDURE [WRITE] Write ( chan : Chan; val : T ) [chan=StdIO.StdOut];
replaces WRITE(value) with T.WriteF(StdIO.StdOut, value) */
/* Procedure Signature */
procedureSignature :=
ident ( '(' formalParams ( ';' formalParams )* ')' )?
( ':' returnedType )?
;
/* Formal Parameters */
formalParams :=
identList ':' ( nonAttrFormalType | variadicFormalParams ) |
attributedFormalParams | allocatingFormalParams
;
/* Attributed Formal Parameters */
attributedFormalParams :=
( CONST | VAR ) identList ':'
( nonAttrFormalType | simpleVariadicFormalType )
;
/* Allocating Formal Parameters */
allocatingFormalParams :=
NEW identList ':' ( pointerTypeIdent | CAST addressTypeIdent )
;
/* Variadic Formal Parameters */
variadicFormalParams :=
ARGLIST reqNumOfArgs? OF varArgDescriptor
;
/* Variadic Argument Descriptor */
varArgDescriptor :=
'{' varArgComponent ( ';' varArgComponent )+ '}' |
nonAttrFormalType )
;
/* Variadic Argument Component */
varArgComponent :=
( CONST | VAR )? identList ':' nonAttrFormalType
;
/* Variadic Formal Parameters (C-FFI) */
variadicFormalParamsCFFI :=
ARGLIST
( OF varArgDescriptor '|' terminator |
argcRef OF varArgDescriptor |
'[' fmtStrRef ']' )
;
/* Terminator */
alias terminator = constQualident ;
/* Constant Qualified Identifier */
alias constQualident = qualident ;
/* Argument Counter Reference */
alias argcRef = StdIdent ;
/* Format String Reference */
alias fmtStrRef = StdIdent ;
/*** Implementation and Program Module Syntax ***/
/* Implementation or Program Module */
implOrPrgmModule :=
IMPLEMENTATION MODULE moduleIdent ';'
privateImport* block moduleIdent '.'
;
/* Private Import */
privateImport :=
IMPORT libIdent ( ',' libIdent )* ';'
;
/* Block */
block :=
declaration*
BEGIN statementSequence END
;
/* Declaration */
declaration :=
ALIAS ( aliasDeclaration ';' )+ |
CONST ( ident '=' constExpression ';' )+ |
TYPE ( typeDeclaration ';' )+ |
VAR ( varOrFieldDeclaration ';' )+ |
procedureHeader ';' block Ident ';' |
toDoList ';'
;
/* Alias Declaration */
aliasDeclaration :=
namedAliasDecl | wildcardAliasDecl
;
/* Named Alias Declaration */
namedAliasDecl :=
aliasName
( '=' qualifiedName | ( ',' aliasName )* '=' qualifiedWildcard )
;
/* Alias Name */
alias aliasName = StdIdent ;
/* Qualified Name */
alias qualifiedName = qualident ;
/* Qualified Wildcard */
qualifiedWildcard :=
qualident '.*'
;
/* Wildcard Alias Declaration */
wildcardAliasDecl :=
'*' '=' qualifiedWildcard
;
/* Type Declaration */
typeDeclaration :=
Ident '=' ( indeterminateType | type )
;
/* Indeterminate Type */
indeterminateType :=
IN RECORD fieldDeclaration ( fieldDeclaration ';' ) indeterminateField END
;
/* Field Declaration */
alias fieldDeclaration = varOrFieldDeclaration ;
/* Indeterminate Field */
indeterminateField :=
'+' Ident ':' BARE ARRAY discriminantFieldIdent OF typeIdent
;
/* Discriminant Field Identifier */
alias discriminantFieldIdent = ident ;
/* Variable or Field Declaration */
varOrFieldDeclaration :=
identList ':' ( typeIdent | anonType )
;
/* Anonymous Type */
BARE? ARRAY valueCount OF typeIdent |
subrangeType |
procedureType
;
/* Statement Sequence */
statementSequence :=
statement ( ';' statement )*
;
/* Statement */
statement :=
emptyStatement | memMgtOperation | updateOrProcCall | returnStatement |
ifStatement | caseStatement | loopStatement | whileStatement |
repeatStatement | forStatement | EXIT
;
/* Empty Statement */
alias emptyStatement = toDoList ;
/* TO DO List */
toDoList :=
TO DO trackingRef? taskToDo ( ';' taskToDo )* END
;
/* Issue Tracking Reference */
trackingRef :=
'(' issueId ',' weight ')'
;
/* Issue ID */
alias issueId = wholeNumber ;
/* Whole Number */
alias wholeNumber = NumberLiteral ;
/* TO DO Task */
taskToDo :=
description ( ',' estimatedHours )?
;
/* Description */
alias description = StringLiteral ;
/* Weight */
alias weight = constExpression ;
/* Estimated Hours */
alias estimatedHours = constExpression ;
/* Memory Management Operation */
memMgtOperation :=
NEW designator ( OF initSize | := initValue ) |
RETAIN designator |
RELEASE designator
;
/* Initialisation Size */
alias initSize = expression ;
/* Initialisation Value */
alias initValue = expression ;
/* Update Or Procedure Call */
updateOrProcCall :=
designator ( IncOrDecSuffix | ':=' expression | '(' expressionList ')' )? |
COPY designator ':=' expression
;
/* Increment Or Decrement Suffix */
.IncOrDecSuffix := '++' | '--' ;
/* RETURN Or YIELD Statement */
returnStatement :=
( RETURN | YIELD ) expression?
;
/* IF Statement */
ifStatement :=
IF boolExpression THEN statementSequence
( ELSIF boolExpression THEN statementSequence )*
( ELSE statementSequence )?
END
;
/* Boolean Expression */
alias boolExpression = expression ;
/* CASE Statement */
caseStatement :=
CASE expression OF ( '|' case )+ ( ELSE statementSequece )? END
;
/* Case */
case :=
caseLabels ( ',' caseLabels )* : StatementSequence
;
/* Case Labels */
caseLabels :=
constExpression ( .. constExpression )?
;
/* LOOP Statement */
loopStatement :=
LOOP statementSequence END
;
/* WHILE Statement */
whileStatement :=
WHILE boolExpression DO statementSequence END
;
/* REPEAT Statement */
repeatStatement :=
REPEAT statementSequence UNTIL boolExpression
;
/* FOR Statement */
forStatement :=
FOR forLoopVariants IN iterableExpr DO statementSequence END
;
/* FOR Loop Variants */
forLoopVariants :=
accessor ascOrDesc? ( ',' value )?
;
/* Accessor */
alias accessor = ident ;
/* Value */
alias value = ident ;
/* Ascender Or Descender */
alias ascOrDesc = IncOrDecSuffix ;
/* Iterable Expression */
iterableExpr :=
ordinalRange OF ordinalType | designator
;
/* Ordinal Range */
ordinalRange :=
'[' firstValue '..' lastValue ']'
;
/* First Value */
alias firstValue = expression ;
/* Last Value */
alias lastValue = expression ;
/* Ordinal Type */
alias ordinalType = typeIdent ;
/* Designator */
designator :=
qualident designatorTail?
;
/* Designator Tail */
designatorTail :=
( ( '[' exprListOrSlice ']' | '^' ) ( '.' ident )* )+
;
/* Expression List Or Slice */
exprListOrSlice :=
expression ( exprListTail | sliceTail )?
;
/* Expression List Tail */
exprListTail :=
( ',' expression )+
;
/* Slice Tail */
sliceTail :=
'..' expression?
;
/* Expression List */
expressionList :=
expression ( ',' expression )*
;
/* Expression */
expression :=
simpleExpression ( OperL1 simpleExpression )?
;
/* Level-1 Operator */
.OperL1 :=
'=' | '#' | '<' | '<=' | '>' | '>=' | IN | IdentityOp
;
/* Identity Operator */
alias IdentityOp = '==' ;
/* Simple Expression */
simpleExpression :=
term ( OperL2 term )* | '-' simpleFactor
;
/* Level-2 Operator */
.OperL2 :=
'+' | '-' | OR | ConcatOp | SetDiffOp
;
/* Concatenation Operator */
alias ConcatOp = '&' ;
/* Set Difference Operator */
alias SetDiffOp = '\' ;
/* Term */
term :=
simpleTerm ( OperL3 simpleTerm )*
;
/* Level-3 Operator */
.OperL2 :=
'*' | '/' | DIV | MOD | AND
;
/* Simple Term */
simpleTerm :=
NOT? factor
;
/* Simple Term (experimental) */
simpleTerm2 :=
factor ( ExpOp factor )* | NOT factor
;
/* Exponentiation Operator */
alias ExpOp = '**' ;
/* Factor */
factor :=
simpleFactor ( TypeConvOp typeIdent )?
;
/* Type Conversion Operator */
alias TypeConvOp = '::' ;
/* Simple Factor */
simpleFactor :=
NumberLiteral | StringLiteral |
structuredValue | designatorOrFuncCall | '(' expression ')'
;
/* Designator Or Function Call */
designatorOrFuncCall :=
designator ( '(' expressionList? ')' )?
;
/* Structured Value */
structuredValue :=
'{' valueComponent ( ',' valueComponent )* '}'
;
/* Value Component */
valueComponent :=
constExpression ( ( '..' | 'BY' ) constExpression )? |
runtimeExpression
;
/* Runtime Expression */
alias runtimeExpression = expression ;
/*** Blueprint Syntax ***/
/* Blueprint */
blueprint :=
BLUEPRINT blueprintIdent ( '[' blueprintToRefine ']' )?
( FOR blueprintForTypeToExtend )?
( ';' REFERENTIAL identList )? ';'
MODULE TYPE '='
( typeClassification ( ';' literalCompatibility )? | NONE ) ';'
constraint* requirement* END blueprintIdent '.'
;
/* Blueprint Identifier */
alias blueprintIdent = StdIdent ;
/* Blueprint To Refine */
alias blueprintToRefine = blueprintIdent ;
/* Blueprint For Type To Extend */