WLP4 Typed Intermediate (.wlp4ti) Format

A .wlp4ti file (pronounced woolpty?) is a text file containing a representation of a parse tree for a WLP4 program. It has the same structure as a .wlp4i file, except that lines corresponding to expression nodes in the parse tree are annotated with the type of the expressions. Once a parse tree for a WLP4 program has been annotated with type information during semantic analysis, this format can be produced by performing a preorder traversal of the tree:

• For nodes representing terminals, print the token kind and lexeme (or BOF BOF or EOF EOF for the BOF and EOF nodes).
  If the kind of the token is NUM or NULL, or if the kind of the token is an ID and the ID has a type (i.e., it represents a variable name rather than a procedure name), print a space, then a colon (:), then another space, then the type of the value represented by the node (int or int*).
  Finally, print a newline.
• For nodes representing nonterminals, print the rule used to expand the nonterminal.
  If the left hand side of the rule is expr, term, factor or lvalue, print a space, then a colon (:), then another space, then the type of the expression rooted at the node (int or int*).
  Finally, print a newline, and processed each child subtree recursively from left to right.

Example

WLP4 program:

int wain(int* start, int size) { 
  int* end = NULL;
  end = start + size;
  while(start < end) {
    println(*start);
  }
  return 241;
}

Original .wlp4i file (no type information) start BOF procedures EOF BOF BOF procedures main main INT WAIN LPAREN dcl COMMA dcl RPAREN LBRACE dcls statements RETURN expr SEMI RBRACE INT int WAIN wain LPAREN ( dcl type ID type INT STAR INT int STAR * ID start COMMA , dcl type ID type INT INT int ID size RPAREN ) LBRACE { dcls dcls dcl BECOMES NULL SEMI dcls .EMPTY dcl type ID type INT STAR INT int STAR * ID end BECOMES = NULL NULL SEMI ; statements statements statement statements statements statement statements .EMPTY statement lvalue BECOMES expr SEMI lvalue ID ID end BECOMES = expr expr PLUS term expr term term factor factor ID ID start PLUS + term factor factor ID ID size SEMI ; statement WHILE LPAREN test RPAREN LBRACE statements RBRACE WHILE while LPAREN ( test expr LT expr expr term term factor factor ID ID start LT < expr term term factor factor ID ID end RPAREN ) LBRACE { statements statements statement statements .EMPTY statement PRINTLN LPAREN expr RPAREN SEMI PRINTLN println LPAREN ( expr term term factor factor STAR factor STAR * factor ID ID start RPAREN ) SEMI ; RBRACE } RETURN return expr term term factor factor NUM NUM 241 SEMI ; RBRACE } EOF EOF

Type-annotated .wlp4ti file start BOF procedures EOF BOF BOF procedures main main INT WAIN LPAREN dcl COMMA dcl RPAREN LBRACE dcls statements RETURN expr SEMI RBRACE INT int WAIN wain LPAREN ( dcl type ID type INT STAR INT int STAR * ID start : int* COMMA , dcl type ID type INT INT int ID size : int RPAREN ) LBRACE { dcls dcls dcl BECOMES NULL SEMI dcls .EMPTY dcl type ID type INT STAR INT int STAR * ID end : int* BECOMES = NULL NULL : int* SEMI ; statements statements statement statements statements statement statements .EMPTY statement lvalue BECOMES expr SEMI lvalue ID : int* ID end : int* BECOMES = expr expr PLUS term : int* expr term : int* term factor : int* factor ID : int* ID start : int* PLUS + term factor : int factor ID : int ID size : int SEMI ; statement WHILE LPAREN test RPAREN LBRACE statements RBRACE WHILE while LPAREN ( test expr LT expr expr term : int* term factor : int* factor ID : int* ID start : int* LT < expr term : int* term factor : int* factor ID : int* ID end : int* RPAREN ) LBRACE { statements statements statement statements .EMPTY statement PRINTLN LPAREN expr RPAREN SEMI PRINTLN println LPAREN ( expr term : int term factor : int factor STAR factor : int STAR * factor ID : int* ID start : int* RPAREN ) SEMI ; RBRACE } RETURN return expr term : int term factor : int factor NUM : int NUM 241 : int SEMI ; RBRACE } EOF EOF