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Compiling and loading the expression evaluator and parser (Expr/README.TXT)
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Archive expr.zip contains the files used below.

A. Generating and compiling the lexer and parser for the expression
   language:

   fslex --unicode ExprLex.fsl
   fsyacc --module ExprPar ExprPar.fsy
   fsi -r FSharp.PowerPack.dll Absyn.fs ExprPar.fs ExprLex.fs Parse.fs

   open Parse;;
   fromString "2 + 3 * 4";;     

   #q;;


B. Generating and compiling the lexer and parser for the expression
   language, and loading the interpreter eval, the compiler (to simple
   stack machine code) scomp, and the simple stack machine seval:

   fslex --unicode ExprLex.fsl
   fsyacc --module ExprPar ExprPar.fsy
   fsi -r FSharp.PowerPack.dll Absyn.fs ExprPar.fs ExprLex.fs Parse.fs Expr.fs

   open Parse;;
   open Expr;;
   run (fromString "2 + 3 * 4");;
   eval (fromString "2 + x * 4") [("x", 3)];;
   eval (fromString "let x = 1+2 in 2 + x * 4 end") [];;

   let code1 = scomp (fromString "2 + 3 * 4") [];;
   seval code1 [];;

   let code2 = scomp (fromString "2 + x * 4") [Bound "x"];;
   seval code2 [3];;

   let code3 = scomp (fromString "let x = 1+2 in 2 + x * 4 end") [];;
   seval code3 [];;

   #q;;