function mf(i)=i*3);
a=2*mf(2)
b=sin(45)*4;
c=mf(2)+sin(45);

grammar org.xtext.example.test.Test with org.eclipse.xtext.common.Terminals

generate test "http://www.xtext.org/example/test/Test"


Package:
	Statements;
	
Statements:
	 (statements+=Statement)+
;

Statement:
	Assignment";"
	|NamedFunctionDefinition
;


Number:
	intPart=INT ("." decimalPart=INT)? |
	"." decimalPart=INT
;


Expr returns Expression: ExprLet

;

ExprLet returns Expression:
	(lets+=LetClause)* in=ExprIndexedHead
;

ExprIndexedHead returns Expression:
	arr=ExprElvis ("[" index=ExprElvis "]")?
;

ExprElvis returns Expression:
	cond=ExprOr ("?" if=ExprOr ":" else=ExprOr)?
;

ExprOr returns Expression:
	ExprAnd ({Expression.left=current} op='||' right=ExprAnd)*
;

ExprAnd returns Expression:
	ExprRel ({Expression.left=current} op='&&' right=ExprRel)*
;

ExprRel returns Expression:
	ExprAdd ({Expression.left=current} op=('>='|'>'|'=='|'!='|'<='|'<') right=ExprAdd)*
;

ExprAdd returns Expression:
	ExprMul ({Expression.left=current} op=('+' | '-') right=ExprMul)*
;

ExprMul returns Expression:
	ExprUni ({Expression.left=current} op=('*' | '/' | '%') right=ExprUni)*
;

ExprUni returns Expression:
	{Expression} (op=('-' | '!' | '+'))? right=ExprAtomic
;

ExprAtomic:
	FunctionCall |
	"(" Expr ")" |
	{NumberLiteral} val=Number |
	{StringLiteral} val=STRING |
	VariableReference 
;

VariableReference:
	{BuiltinVar} "$" name=ID |
	{UserVar} name=ID
;

LetClause:
	{LetClause} "let""("ass=Assignments?")"
;

NamedFunctionDefinition:
	"function" name=ID "(" params=Parameters? ")=" body=Expr ";"  
;

BuiltinFunctions:
	name=NamedBuiltin
;

// Works with user defined functios
//FunctionCall:
//	function=[NamedFunctionDefinition|ID] "(" args=Arguments? ")"
//;

// Works with builtin functions
//FunctionCall:
//	function=BuiltinFunctions "(" args=Arguments? ")"
//;

// This doesn't work
FunctionCall:
	function=[BuiltinFunctions|NamedFunctionDefinition|ID] "(" args=Arguments? ")"
;

Parameters:
	parameters+=Parameter ("," parameters+=Parameter)*
;

AssignmentOrExpr:
	var=VariableReference ("=" tail=Expr) |
	val=Expr
;

Parameter:
	AssignmentOrExpr // TODO: Name from Assignment
;

Arguments:
	arguments+=Argument ("," arguments+=Argument)*
;

Argument:
	Expr | Assignment
;

Assignments:
	assignments+=Assignment ("," assignments+=Assignment)*
;

Assignment:
	name=VariableReference "=" val=Expr
;

NamedBuiltin:
	'abs' | 'sin' | 'cos' | 'tan'
;


//