CopperHead.grammar

%header%
GRAMMARTYPE = "LL"

%tokens%
WHITESPACE = <<[ \t\n\r]+>> %ignore%  //ignore tag to discard such tokens

STRING = <<\'.*?\'>>
INTEGER = <<([-|+]?[0-9]+)>>  //includes shorts and bytes

//value literals
TRUE = "true"
FALSE = "false"

//control flow keywords
WHILE = "while"
IF = "if"

//built in funcs with 1 argument
//ADD1 = "add1"
//SUB1 = "sub1"
//ISNUM = "isNum"
//ISBOOL = "isBool"

//built-in type names
INT = "int"
STR = "string"
BOOL = "bool"


//other keywords
LET = "let"
DEF = "def"
SET = "set"
VOID = "void"

NAME = <<[a-zA-Z][a-zA-Z0-9_]*>>  //reduce spaces between "<<" and ">>"

//operators
PLUS = "+"
MINUS = "-"
MULT = "*"
LESS = "<"
GREAT = ">"
EQUAL = "="
NOT_EQ = "!="
GR_EQ = ">=" 
LS_EQ = "<="

COLON = ":"
EXPONENT = "^"

OP_PAREN = "("
CL_PAREN = ")"


%productions%

program = (expr+);

expr = (atom
       | (OP_PAREN funcDef CL_PAREN)
       | (OP_PAREN letDec CL_PAREN)
	   | (OP_PAREN ifExpr CL_PAREN)
	   | (OP_PAREN binOp CL_PAREN)
	   | (OP_PAREN setVar CL_PAREN)
	   | (OP_PAREN funcCall CL_PAREN)
	   | (OP_PAREN whileLoop CL_PAREN));
	   
funcDef = DEF NAME ((OP_PAREN (NAME COLON type) CL_PAREN)+ | VOID) COLON (type | VOID) (expr)+ ;
letDec = LET OP_PAREN (OP_PAREN (NAME COLON type)  expr CL_PAREN)+ CL_PAREN (expr)+ ;
ifExpr = IF expr expr expr;
binOp = (PLUS | MINUS | MULT | LESS | GREAT | EQUAL) expr expr;
setVar = SET NAME expr;
funcCall = NAME (expr)*;
whileLoop = WHILE expr (expr)*;
	   
type = (INT | BOOL | STR);

atom = ( ( [MINUS] INTEGER) | FALSE | TRUE | STRING | NAME);