From 22659d8fedad11d43134cfc860b65841536035c3 Mon Sep 17 00:00:00 2001
From: Dmitry Boulytchev <dboulytchev@gmail.com>
Date: Sun, 25 Feb 2018 17:39:54 +0300
Subject: [PATCH] Intermediate

---
 regression/test000.log |  0
 src/Driver.ml          |  2 +-
 src/Language.ml        | 36 ++++++++++++++++++++++++++++++------
 3 files changed, 31 insertions(+), 7 deletions(-)
 delete mode 100644 regression/test000.log

diff --git a/regression/test000.log b/regression/test000.log
deleted file mode 100644
index e69de29bb..000000000
diff --git a/src/Driver.ml b/src/Driver.ml
index 4082ccbab..67dd012d7 100644
--- a/src/Driver.ml
+++ b/src/Driver.ml
@@ -6,6 +6,7 @@ let parse infile =
     (object
        inherit Matcher.t s
        inherit Util.Lexers.decimal s
+       inherit Util.Lexers.ident ["read"; "write"] s
        inherit Util.Lexers.skip [
 	 Matcher.Skip.whitespaces " \t\n";
 	 Matcher.Skip.lineComment "--";
@@ -18,7 +19,6 @@ let parse infile =
 let main =
   try
     let interpret  = Sys.argv.(1) = "-i"  in
-    let stack      = Sys.argv.(1) = "-s"  in
     let infile     = Sys.argv.(2) in
     match parse infile with
     | `Ok prog ->
diff --git a/src/Language.ml b/src/Language.ml
index 35ffeeb06..9b6d9ac72 100644
--- a/src/Language.ml
+++ b/src/Language.ml
@@ -43,8 +43,7 @@ module Expr =
  
        Takes a state and an expression, and returns the value of the expression in 
        the given state.
-     *)
-                                                       
+     *)                                                       
     let to_func op =
       let bti   = function true -> 1 | _ -> 0 in
       let itb b = b <> 0 in
@@ -71,9 +70,28 @@ module Expr =
       | Var   x -> st x
       | Binop (op, x, y) -> to_func op (eval st x) (eval st y)
 
-    (* Statement parser *)
-    ostap (
-      parse: empty {failwith "Not implemented yet"}
+    (* Expression parser *)
+    ostap (                                      
+      parse:
+	  !(Ostap.Util.expr 
+             (fun x -> x)
+	     (Array.map (fun (a, s) -> a, 
+                           List.map  (fun s -> ostap(- $(s)), (fun x y -> Binop (s, x, y))) s
+                        ) 
+              [|                
+		`Lefta, ["!!"];
+		`Lefta, ["&&"];
+		`Nona , ["=="; "!="; "<="; "<"; ">="; ">"];
+		`Lefta, ["+" ; "-"];
+		`Lefta, ["*" ; "/"; "%"];
+              |] 
+	     )
+	     primary);
+      
+      primary:
+        n:DECIMAL {Const n}
+      | x:IDENT   {Var x}
+      | -"(" parse -")"
     )
 
   end
@@ -107,7 +125,13 @@ module Stmt =
                                 
     (* Statement parser *)
     ostap (
-      parse: empty {failwith "Not implemented yet"}
+      parse:
+        s:stmt ";" ss:parse {Seq (s, ss)}
+      | stmt;
+      stmt:
+        "read" "(" x:IDENT ")"          {Read x}
+      | "write" "(" e:!(Expr.parse) ")" {Write e}
+      | x:IDENT ":=" e:!(Expr.parse)    {Assign (x, e)}            
     )
       
   end