Parsing parenthesized expressions.

aktemur · Nov 9, 2017 · 169f372 · 169f372
1 parent acd8eb5
commit 169f372
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diff --git a/Deve/lexer.ml b/Deve/lexer.ml
@@ -11,6 +11,7 @@ type token = INT of int
            | PLUS | STAR | MINUS | SLASH
            | LET | EQUALS | IN
            | IF | THEN | ELSE
+           | LPAR | RPAR
            | ERROR of char
            | EOF
 ;;
@@ -50,6 +51,8 @@ let rec tokenize chars =
   | ' '::rest -> tokenize rest
   | '\t'::rest -> tokenize rest
   | '\n'::rest -> tokenize rest
+  | '('::rest  -> LPAR::(tokenize rest)
+  | ')'::rest  -> RPAR::(tokenize rest)
   | c::rest when isDigit(c) ->
      tokenizeInt rest (digitToInt c)
   | c::rest when isLowercaseLetter(c) ->

diff --git a/Deve/parser.ml b/Deve/parser.ml
@@ -113,6 +113,10 @@ and parseLevel4Exp tokens =
   | INT i :: rest -> (CstI i, rest)
   | NAME x :: rest -> (Var x, rest)
   | BOOL b :: rest -> (CstB b, rest)
+  | LPAR::rest ->
+     let (e, tokens1) = parseExp rest in
+     let rest1 = consume RPAR tokens1 in
+     (e, rest1)
   | t::rest -> failwith ("Unsupported token: " ^ toString(t))
 
 (* parseMain: token list -> exp *)