diff options
| author | hallgren <hallgren@chalmers.se> | 2011-10-20 14:36:30 +0000 |
|---|---|---|
| committer | hallgren <hallgren@chalmers.se> | 2011-10-20 14:36:30 +0000 |
| commit | ed451653bd9fa4d835cb263c06d0ecb9133b9935 (patch) | |
| tree | cf6cc1e56c5cac76d4c9fb6c09a6bad456e3c151 /src/compiler/GF/Grammar | |
| parent | e5accc0d8d3c6d9cace9d4aff482ab285bf7e01b (diff) | |
Introduce an explicit error value in the Term type
This makes it easier to treat run-time errors (e.g. caused by calls to
Predef.error) in a way that is more typical for a lazy functional language.
Diffstat (limited to 'src/compiler/GF/Grammar')
| -rw-r--r-- | src/compiler/GF/Grammar/Grammar.hs | 2 | ||||
| -rw-r--r-- | src/compiler/GF/Grammar/Printer.hs | 1 |
2 files changed, 2 insertions, 1 deletions
diff --git a/src/compiler/GF/Grammar/Grammar.hs b/src/compiler/GF/Grammar/Grammar.hs index 686164539..ae29ab6d5 100644 --- a/src/compiler/GF/Grammar/Grammar.hs +++ b/src/compiler/GF/Grammar/Grammar.hs @@ -161,7 +161,7 @@ data Term = | Alts Term [(Term, Term)] -- ^ alternatives by prefix: @pre {t ; s\/c ; ...}@ | Strs [Term] -- ^ conditioning prefix strings: @strs {s ; ...}@ - + | Error String -- ^ error values returned by Predef.error deriving (Show, Eq, Ord) data Patt = diff --git a/src/compiler/GF/Grammar/Printer.hs b/src/compiler/GF/Grammar/Printer.hs index ef31af3bb..5fa9121fc 100644 --- a/src/compiler/GF/Grammar/Printer.hs +++ b/src/compiler/GF/Grammar/Printer.hs @@ -192,6 +192,7 @@ ppTerm q d (Typed e t) = char '<' <> ppTerm q 0 e <+> colon <+> ppTerm q 0 t <> ppTerm q d (ImplArg e) = braces (ppTerm q 0 e)
ppTerm q d (ELincat cat t) = prec d 4 (text "lincat" <+> ppIdent cat <+> ppTerm q 5 t)
ppTerm q d (ELin cat t) = prec d 4 (text "lin" <+> ppIdent cat <+> ppTerm q 5 t)
+ppTerm q d (Error s) = prec d 4 (text "Predef.error" <+> str s)
ppEquation q (ps,e) = hcat (map (ppPatt q 2) ps) <+> text "->" <+> ppTerm q 0 e
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