rtk-0.11: test-grammars/haskell.pg

grammar 'Haskell';

Haskell = Module ;

Module = 'module' ModId ExportsOpt 'where' Body | Body;

ExportsOpt = ( '(' ExportsList (',')?')' )?;

ExportsList = Export * ',' ;

Export = 'module' ModId | QVar | QTyCon ( '(' '..' ')' | '(' CNameList ')')? | QTyCls ( '(' '..' ')' | '(' QVarList ')')?;

Body = '{' (ImpDeclList (';' TopDecls)? | ImpDeclList) '}' ;

ImpDeclList = ImpDecl + ';';

ImportList = Import * ',' ;

Var = varid;
Con = conid;

ModIdList = (ModId '.')*;

QVarId = ModIdList varid;
QVar = QVarId;

QTyCls = ModIdList TyCls;

QTyCon = ModIdList TyCon;

CName = Var | Con ;

CNameList = CName * ',' ;

QVarList = QVar * ',' ;

Import = Var | TyCon ( '(' '..' ')' | '(' CNameList ')' )? ;

OptQualified = ('qualified')?;
OptQualifiedAs = ('as' ModId)?;
OptImpSpec = '(' ImportList (',')? ')' ;

ImpDecl = 'import' OptQualified ModId OptQualifiedAs OptImpSpec? ;

TopDecls = TopDecl * ';';

TopDecl = 'type' SimpleType '=' Type
    | 'data' OptContext SimpleType '=' Constrs OptDeriving
    | Decl;

Decl = GenDecl |
    (FunLhs | Pat) Rhs ;

OptContext = (Context '=>')? ;

GenDecl = Vars '::' OptContext Type
    | Fixity OptInteger Ops;

OptInteger = (integer)? ;

Ops = Op * ',' ;

Fixity = 'infixl' | 'infixr' | 'infix' ;

FunLhs = Var ;

# TODO: incomplete (issue #30) -- only constructor patterns over plain
# variables; the variable-only case is already covered by FunLhs
Pat = Con (Var)* ;

OptWhere = ('where' Decls) ;

DeclList = Decl * ';' ;

Decls = '{' DeclList '}' ;

Rhs = '=' Exp OptWhere
    | GdRhs OptWhere;

OptGdRhs = (GdRhs)? ;

# An optional guard expression. (Formerly written with an empty first
# alternative 'Gd = | ExpI ;', hand-parser-only syntax that grammar.pg cannot
# derive; a top-level option normalizes to exactly the same empty-or-present
# alternatives.)
Gd = ExpI? ;

OptExpTypeSignature = ('::' OptContext Type)?;

Exp = ExpI OptExpTypeSignature ;

ExpI = ExpI (QOp ExpI)*;

GdRhs = Gd '=' Exp OptGdRhs ;

Constrs = Constr * '|' ;

Constr = Con '{' FieldDeclList '}';

FieldDeclList = FieldDecl * ',' ;

FieldDecl = Vars '::' (Type | '!' AType) ;

Vars = Var * ',' ;

OptDeriving = (Deriving)? ;

Deriving = 'deriving' (DClass | '(' DClassList ')' ) ;

DClassList = DClass * ',' ;

DClass = QTyCls ;

Context = Class | '(' ClassList ')' ;

ClassList = Class * ',' ;

Class = QTyCls TyVar | QTyCls '(' TyVar ATypeList ')';

Type = BType ('->' Type)? ;

BType = (BType)? AType ;

ATypeList = AType * ;

AType = TyVar 
 | GTyCon
 | '(' (TypeList /*| ',' +*/) ')' # TODO: this should be fixed
 | '[' (Type)? ']';

GTyCon = QTyCon
 | '(' '->' ')' ;

TypeList = Type * ',' ;

SimpleType = TyCon TyVars ;

TyVars = TyVar * ; 

conid = [A-Z] [a-zA-Z_0-9]* ;
varid = [a-zA-Z_] [a-zA-Z_0-9]* ;
TyVar = varid ;

TyCon = conid ;
ModId = conid ;
TyCls = conid ;
Op = varid | conid ;

# TODO: incomplete (issue #30) -- symbolic and backtick-quoted operators are
# not covered; an optionally qualified Op, mirroring QVarId
QOp = ModIdList Op ;

decimal = [0-9]+ ;
octal = [0-7]+ ;
hexadecimal = [0-9A-Fa-f]+ ;

integer = decimal
    | ('0o' | '0O') octal
    | ('0x' | '0X') hexadecimal ;

whitespace = [ \t\n] ;

Ignore: comment = '--' .* [\n] ;
ncomment = '{-' (.|[\n])* '-}' ;
th = '$(' ([^\)]|[\n])* ')' ;