%start prog

%token IDENT
%token STRINGLIT
%token INTLIT
%token INTEGER STRING
%token IF WHILE RETURN PRINT ELSE
%token EQ NEQ LT GT LEQ GEQ
%left  PLUS MINUS
%left  MULT DIV
%right UMINUS
%token OPENPAR CLOSEPAR
%token SEMICOLON COMMA
%token OPENCURLY CLOSECURLY

%token ERROR

%%

prog: /* Nothing */ 
    | prog def 
;

def: vardef
   | fundef
;

vardef: type IDENT SEMICOLON
;

fundef: type IDENT OPENPAR params CLOSEPAR body 
;

type: STRING  
    | INTEGER 
;

params: /* empty */ 
      | paramlist
;

paramlist: param 
         | paramlist COMMA param 
;

param: type IDENT 
;

body: OPENCURLY vardefs stmts CLOSECURLY
;

vardefs: /* empty */ 
       | vardefs vardef
;


stmts: /* empty */
     | stmts stmt
;


stmt: while_stmt 
    | if_stmt    
    | ret_stmt   
    | print_stmt 
    | assign     
    | funcall_stmt
;

while_stmt: WHILE OPENPAR boolexpr CLOSEPAR body 
;

if_stmt: IF OPENPAR boolexpr CLOSEPAR body
       | IF OPENPAR boolexpr CLOSEPAR body ELSE body
;

ret_stmt: RETURN expr SEMICOLON
;

 print_stmt: PRINT expr SEMICOLON 
;


assign: IDENT EQ expr SEMICOLON
;

funcall_stmt: funcall SEMICOLON 
;

boolexpr: expr EQ expr  
        | expr NEQ expr 
        | expr LT expr  
        | expr GT expr  
        | expr LEQ expr 
        | expr GEQ expr 
;

expr: funcall 
    | INTLIT  
    | IDENT   
    | STRINGLIT
    | OPENPAR expr CLOSEPAR 
    | expr PLUS expr  
    | expr MINUS expr 
    | expr MULT expr  
    | expr DIV expr   
    | MINUS expr %prec UMINUS 
;

funcall: IDENT OPENPAR args CLOSEPAR
;

args: /* empty */
    | arglist 
;

arglist: expr
       |expr COMMA arglist
;

%%