+++ /dev/null
-(* L1 Compiler
- * L1 grammar
- * Author: Kaustuv Chaudhuri <kaustuv+@cs.cmu.edu>
- * Modified: Frank Pfenning <fp@cs.cmu.edu>
- *)
-
-structure A = Ast
-
-(* for simplicity, we only mark expressions, not statements *)
-
-(* mark e with region (left, right) in source file *)
-fun mark (e, (left, right)) = A.Marked (Mark.mark' (e, ParseState.ext (left, right)))
-
-(* create lval from expression; here just an id *)
-(* generates error if not an identifier *)
-fun make_lval (A.Var(id)) ext = id
- | make_lval (A.Marked(marked_exp)) ext =
- make_lval (Mark.data marked_exp) (Mark.ext marked_exp)
- | make_lval _ ext = ( ErrorMsg.error ext "not a variable" ;
- Symbol.bogus )
-
-(* expand_asnop (exp1, "op=", exp2) region = "exp1 = exp1 op exps"
- * or = "exp1 = exp2" if asnop is "="
- * generates error if exp1 is an lval (identifier)
- * syntactically expands a compound assignment operator
- *)
-fun expand_asnop (exp1, NONE, exp2) (left, right) =
- A.Assign(make_lval exp1 NONE, exp2)
- | expand_asnop (exp1, SOME(oper), exp2) (left, right) =
- A.Assign(make_lval exp1 NONE,
- mark(A.OpExp(oper, [exp1, exp2]), (left, right)))
-
-%%
-%header (functor L1LrValsFn (structure Token : TOKEN))
-
-%term
- EOF
- | SEMI
- | INTNUM of Word32.word
- | IDENT of Symbol.symbol
- | RETURN
- | PLUS | MINUS | STAR | SLASH | PERCENT
- | ASSIGN | PLUSEQ | MINUSEQ | STAREQ | SLASHEQ | PERCENTEQ
- | LBRACE | RBRACE
- | LPAREN | RPAREN
- | UNARY | ASNOP (* dummy *)
-
-%nonterm
- program of A.program
- | stms of A.stm list
- | stm of A.stm
- | simp of A.stm
- | return of A.stm
- | exp of A.exp
- | asnop of A.oper option
-
-%verbose (* print summary of errors *)
-%pos int (* positions *)
-%start program
-%eop EOF
-%noshift EOF
-
-%name L1
-
-%left PLUS MINUS
-%left STAR SLASH PERCENT
-%right UNARY
-%left LPAREN
-
-%%
-
-program : LBRACE stms return RBRACE
- (stms@[return])
-
-return : RETURN exp SEMI (A.Return exp)
-
-stms : ([])
- | stm stms (stm :: stms)
-
-stm : simp SEMI (simp)
-simp : exp asnop exp %prec ASNOP
- (expand_asnop (exp1, asnop, exp2) (exp1left, exp2right))
-
-exp : LPAREN exp RPAREN (exp)
- | INTNUM (mark (A.ConstExp(INTNUM),(INTNUMleft,INTNUMright)))
- | IDENT (mark (A.Var(IDENT), (IDENTleft,IDENTright)))
- | exp PLUS exp (mark (A.OpExp (A.PLUS, [exp1,exp2]), (exp1left,exp2right)))
- | exp MINUS exp (mark (A.OpExp (A.MINUS, [exp1,exp2]), (exp1left,exp2right)))
- | exp STAR exp (mark (A.OpExp (A.TIMES, [exp1,exp2]), (exp1left,exp2right)))
- | exp SLASH exp (mark (A.OpExp (A.DIVIDEDBY, [exp1,exp2]), (exp1left,exp2right)))
- | exp PERCENT exp (mark (A.OpExp (A.MODULO, [exp1,exp2]), (exp1left,exp2right)))
- | MINUS exp %prec UNARY (mark (A.OpExp (A.NEGATIVE, [exp]), (MINUSleft,expright)))
-
-asnop : ASSIGN (NONE)
- | PLUSEQ (SOME(A.PLUS))
- | MINUSEQ (SOME(A.MINUS))
- | STAREQ (SOME(A.TIMES))
- | SLASHEQ (SOME(A.DIVIDEDBY))
- | PERCENTEQ (SOME(A.MODULO))