diff options
author | Eduardo Julian | 2018-01-16 22:32:23 -0400 |
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committer | Eduardo Julian | 2018-01-16 22:32:23 -0400 |
commit | 198834d3c3ff0cc70b0521a7341ae66040db2641 (patch) | |
tree | 8285535facb508ee7f91452ebb521a30aa6bf7bd | |
parent | 43b1c20c7ff24759265093c4244c922faf7b27f4 (diff) |
- Added indexed/parameterized monads.
-rw-r--r-- | stdlib/source/lux/control/monad/indexed.lux | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/stdlib/source/lux/control/monad/indexed.lux b/stdlib/source/lux/control/monad/indexed.lux new file mode 100644 index 000000000..dcc3b2067 --- /dev/null +++ b/stdlib/source/lux/control/monad/indexed.lux @@ -0,0 +1,61 @@ +(.module: + lux + (lux (control [monad] + ["p" parser]) + (data (coll [list "list/" Functor<List> Fold<List>])) + [macro] + (macro ["s" syntax #+ Syntax syntax:]))) + +(sig: #export (IxMonad m) + (: (All [p a] + (-> a (m p p a))) + wrap) + + (: (All [ii it io vi vo] + (-> (-> vi (m it io vo)) + (m ii it vi) + (m ii io vo))) + bind)) + +(type: Binding [Code Code]) + +(def: binding + (Syntax Binding) + (p.seq s.any s.any)) + +(type: Context + (#Let (List Binding)) + (#Bind Binding)) + +(def: context + (Syntax Context) + (p.alt (p.after (s.this (' #let)) + (s.tuple (p.some binding))) + binding)) + +(def: (pair-list [binding value]) + (All [a] (-> [a a] (List a))) + (list binding value)) + +(syntax: #export (do monad + [context (s.tuple (p.some context))] + expression) + (macro.with-gensyms [g!bind] + (wrap (list (` (let [(~' @) (~ monad) + {#..wrap (~' wrap) + #..bind (~ g!bind)} (~' @)] + (~ (list/fold (function [context next] + (case context + (#Let bindings) + (` (let [(~+ (|> bindings + (list/map pair-list) + list.concat))] + (~ next))) + + (#Bind [binding value]) + (` ((~ g!bind) + (.function [(~ binding)] + (~ next)) + (~ value))))) + expression + (list.reverse context))))))))) |