%{
/***
 * Shane Beasley
 * EECS 473: Compiler Design
 * Machine Problem 4: Using Bison
 ***/

#include <iostream>
#include <cstddef>
#include <cstdlib>

  extern struct filepos_t
  {
    size_t line, column;
  } tokenPos;

  extern "C" 
  {
    // defined by lex
    int yylex (void);

    inline void yyerror (const char *ptr)
    {
      cerr << "line " << tokenPos.line
	   << ", col " << tokenPos.column
	   << ": " << ptr << endl;
    }
  }

  %}

%union
{
  const char *c_str;
}

%token	<c_str>	KEYWORD_CHAR	KEYWORD_CLASS	KEYWORD_DELETE	KEYWORD_ELSE	KEYWORD_FALSE
%token	<c_str>	KEYWORD_IF	KEYWORD_INT	KEYWORD_NEW	KEYWORD_PRIVATE	KEYWORD_PUBLIC
%token	<c_str>	KEYWORD_RETURN	KEYWORD_TRUE	KEYWORD_VOID	KEYWORD_WHILE

%token	<c_str>	KEYWORD_CIN	KEYWORD_COUT

%token	<c_str>	ARROW_OPERATOR
%token	<c_str>	GREATER_THAN_OR_EQUAL_TO_OPERATOR LESS_THAN_OR_EQUAL_TO_OPERATOR EQUAL_TO_OPERATOR NOT_EQUAL_TO_OPERATOR
%token	<c_str>	LOGICAL_AND_OPERATOR LOGICAL_OR_OPERATOR SHIFT_LEFT_OPERATOR SHIFT_RIGHT_OPERATOR

%token	<c_str>	INTEGER
%token	<c_str>	FLOAT
%token	<c_str>	CHARACTER
%token	<c_str>	IDENTIFIER
%token	<c_str>	STRING

%type	<c_str> type
%type	<c_str>	num
%type	<c_str>	ident

%%

StartPrime
: Start { }
;

Start
: StartItem Start
| // empty
;

StartItem
: varDecl
| classDef
| functDef
| prototype
;

varDecl
: type varList ';' { }
;

varList
: varList ',' varIdent { }
| varIdent { }
;

varIdent
: ptrIdent brackets
;

ptrIdent
: '*' IDENTIFIER
| IDENTIFIER { }
;

brackets
: '[' num ']'
| // empty
;

type
: KEYWORD_INT
| KEYWORD_CHAR
| IDENTIFIER { $$ = $1; }
;

classDef
: KEYWORD_CLASS IDENTIFIER '{' classItems '}' ';' { }
;

classItem
: accessMode classMember
| classMember
;

classItems
: classItem classItems
| /* empty */
;

classMember
: varDecl
| functDef
;

accessMode
: KEYWORD_PUBLIC ':' { }
| KEYWORD_PRIVATE ':' { }
;

pfPrefix
: type '*' IDENTIFIER '(' { }
| type IDENTIFIER '(' { }
| KEYWORD_VOID IDENTIFIER '(' { }
;

pfFormal
: pfPrefix formalParamList ')'
;

prototype
: pfFormal ';' { }
| pfPrefix protoParamList ')' ';' { }
;

functDef
: pfFormal '{' body '}' { }
;

fpItem
: type '*' IDENTIFIER { }
| type IDENTIFIER { }
;

fpItems
: fpItems ',' fpItem { }
| fpItem { }
;

formalParamList
: fpItems
| // empty
;

protoItem
: type '*' { }
| type { }
;

mixedItem
: protoItem
| fpItem
;

protoItemsR
: ',' mixedItem protoItemsR
| // empty
;

protoParamList
: fpItems ',' protoItem protoItemsR { }
| protoItem protoItemsR { }
;

num
: INTEGER { $$ = $1; }
| FLOAT { $$ = $1; }
;

statements
: statement statements
| // empty
;

statement
: lhsIdent '=' expr ';' { }
| KEYWORD_IF '(' expr ')' statement KEYWORD_ELSE statement { }
| KEYWORD_WHILE '(' expr ')' statement { }
| '{' statements '}' { }
| KEYWORD_RETURN expr ';' { }
| fcall ';' { }
| KEYWORD_COUT output ';' { }
| KEYWORD_CIN input ';' { }
;

output
: SHIFT_LEFT_OPERATOR expr outputChain { }
;

outputChain
: SHIFT_LEFT_OPERATOR expr outputChain { }
| // empty
;

input
: SHIFT_RIGHT_OPERATOR lhsIdent inputChain { }
;

inputChain
: SHIFT_RIGHT_OPERATOR lhsIdent inputChain { }
| // empty
;

exprBase
: fcall { }
| num { }
| CHARACTER { }
| STRING { }
| '(' expr ')' { }
| rhsIdent { }
;

expr
: exprBase
| exprBase BOP expr { }
| UOP expr { }
;

callParamListFollow
: ',' expr callParamListFollow
|
;

callParamList
: expr callParamListFollow
| // empty
;

fcall
: lhsIdent '(' callParamList  ')' { }
;

lhsBase
: ident { }
| ident '[' expr ']' { }
;

ident
: IDENTIFIER { }
;

lhsIdent
: lhsBase { }
| lhsBase '.' lhsIdent { }
| lhsBase ARROW_OPERATOR lhsIdent { }
| '*' lhsIdent
;

rhsIdent
: lhsIdent
| '&' lhsIdent
;

BOP
: '+'
| '-'
| '*'
| '/'
| '%'
| '>'
| GREATER_THAN_OR_EQUAL_TO_OPERATOR { }
| '<'
| LESS_THAN_OR_EQUAL_TO_OPERATOR { }
| EQUAL_TO_OPERATOR { }
| NOT_EQUAL_TO_OPERATOR { }
| LOGICAL_AND_OPERATOR { }
| LOGICAL_OR_OPERATOR { }
;

UOP
: '+'
| '-'
| '!'
;

bodyPart
: varDecl
| statement
| prototype
;

body
: bodyPart body
| // empty
;