// ****************
// grammar rules
// this is the grammar for the simple language. it has standard C/Java semantics for its
// statements and function calls.
// this grammar does not implement any precedence or associativity for its arithmetic
// operators, this needs to be implemented with the appropriate parser generator

prog
	:	stmtlist

stmtList
	: stmt
	| stmtList stmt

stmt	
	:	returnType VAR '(' ')' stmt
	|	returnType VAR '(' formalParamList ')' stmt
	|	dataType VAR ('=' exp)? ';'	
	|	VAR '=' exp ';'		
	|	VAR '(' ')' ';'  
	|	VAR '(' actualParamList ')' ';'  
	|	'return' ';'	
	|	'return' exp ';'	
	|	'while' '(' exp ')' stmt
	|	'if' '(' exp ')' stmt	
	|	'if' '(' exp ')' stmt 'else' stmt	
	|	'{' stmt+ '}'	

dataType
	:	'int'
	|	'float'

returnType
	:  'void'
	|	dataType
		
formalParamList
	:	dataType VAR 
	|   formalParamList ',' dataType VAR
	
actualParamList
	:	exp 
	| 	actualParamList ',' exp
	

exp	
	:	exp '==' exp 
	|	exp '<=' exp
	|	exp '+' exp 
	| 	exp '-' exp
	|	exp '*' exp 
	| 	exp '/' exp
	|	atom
	
atom
	:	'(' exp ')'
	|	VAR '(' ')'
	|	VAR '(' actualParamList ')'
	|	VAR	
	|	INT
	|	FLOAT


//*************************************************************************
// lexical analyzer stuff - this will need to be processed by lex/flex

VAR  	:	('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')* 

INT 	:	'-'?'0'..'9'+;

FLOAT   :   '-'?('0'..'9')+ '.' ('0'..'9')* EXPONENT?
    	|   '-'?'.' ('0'..'9')+ EXPONENT?
  		|   	'-'?('0'..'9')+ EXPONENT

EXPONENT : ('e'|'E') ('+'|'-')? ('0'..'9')+