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| author | Gabriel Dos Reis <gdr@axiomatics.org> | 2016-01-17 22:53:01 -0800 |
|---|---|---|
| committer | Gabriel Dos Reis <gdr@axiomatics.org> | 2016-01-17 22:53:01 -0800 |
| commit | d07fc9735f40e545edda456e15dbab783c500f6a (patch) | |
| tree | 4d9fab82a7085b73a4b00d23389935503fdfc90d /src/algebra/indexedp.spad.pamphlet | |
| parent | 5437d438937eb25eb320fef6e4fd6ebc91ca6dc9 (diff) | |
| download | open-axiom-d07fc9735f40e545edda456e15dbab783c500f6a.tar.gz | |
subtractIfCan$CancellationAbelianMonoid: return the more principled Maybe %
Diffstat (limited to 'src/algebra/indexedp.spad.pamphlet')
| -rw-r--r-- | src/algebra/indexedp.spad.pamphlet | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/src/algebra/indexedp.spad.pamphlet b/src/algebra/indexedp.spad.pamphlet index beee92ac..e4dd5805 100644 --- a/src/algebra/indexedp.spad.pamphlet +++ b/src/algebra/indexedp.spad.pamphlet @@ -293,19 +293,19 @@ IndexedDirectProductOrderedAbelianMonoidSup(A:OrderedAbelianMonoidSup,S:OrderedS s: S subtractIfCan(x,y) == - empty? y => x - empty? x => "failed" - x.first.k < y.first.k => "failed" + empty? y => just x + empty? x => nothing + x.first.k < y.first.k => nothing x.first.k > y.first.k => t:= subtractIfCan(x.rest, y) - t case "failed" => "failed" - cons( x.first, t) - u:=subtractIfCan(x.first.c, y.first.c) - u case "failed" => "failed" + t case nothing => nothing + just cons( x.first, t) + u := subtractIfCan(x.first.c, y.first.c) + u case nothing => nothing zero? u => subtractIfCan(x.rest, y.rest) - t:= subtractIfCan(x.rest, y.rest) - t case "failed" => "failed" - cons([x.first.k,u],t) + t := subtractIfCan(x.rest, y.rest) + t case nothing => nothing + just cons([x.first.k,u],t) sup(x,y) == empty? y => x |