Better debug info

1 files changed, 16 insertions, 8 deletions

diff --git a/stream.sml b/stream.sml
index 4ea7f08..3e18f2e 100644
--- a/stream.sml
+++ b/stream.sml
@@ -36,14 +36,9 @@ structure Stream :> STREAM = struct
     bind A1 p
   end z
 
-  fun getcharSure (S as { contents, off, ... }: t) =
-      (String.sub (contents, off), updateStream S s#off (off + 1) %)
-
-  fun getchar stream =
-    (fn (c, s) => (SOME c, s)) $ getcharSure stream handle
-        Subscript => (NONE, stream)
-
-  fun getcharEx stream = getcharSure stream handle Subscript => raise EOF
+  fun getchar (S as { contents, off, ... }: t) =
+    (SOME $ String.sub (contents, off), updateStream S s#off (off + 1) %)
+      handle Subscript => (NONE, S)
 
   fun ungetc ({ off = 0, ... }: t) =
       raise UngetcError
@@ -84,6 +79,19 @@ structure Stream :> STREAM = struct
 
   fun getOffset ({ off, ... }: t) = off
 
+  fun isFirstOnLine ({ contents, ... }: t) off =
+  let
+    fun check (~1) = true
+      | check off =
+        case String.sub (contents, off) of
+          #"\n" => true
+        | #" " => check (off - 1)
+        | #"\t" => check (off - 1)
+        | _ => false
+  in
+    check (off - 1)
+  end
+
   fun getPosRaw off (S as { cache = (prevOff, line, col), fname,
     contents, ... }: t) =
   let