Commit 9a734fe7 authored by simonpj's avatar simonpj
Browse files

[project @ 1999-06-28 16:40:18 by simonpj]

Add explanatory comments
parent b01ae32e
......@@ -209,6 +209,21 @@ simplifyPgm (imported_rule_ids, rule_lhs_fvs)
-- Glom all binds together in one Rec, in case any
-- transformations have introduced any new dependencies
--
-- NB: the global invariant is this:
-- *** the top level bindings are never cloned, and are always unique ***
--
-- We sort them into dependency order, but applying transformation rules may
-- make something at the top refer to something at the bottom:
-- f = \x -> p (q x)
-- h = \y -> 3
--
-- RULE: p (q x) = h x
--
-- Applying this rule makes f refer to h, although it doesn't appear to in the
-- source program. Our solution is to do this occasional glom-together step,
-- just once per overall simplfication step.
let { recd_binds = [Rec (flattenBinds binds)] };
(termination_msg, it_count, counts_out, binds') <- iteration us 1 zeroSimplCount recd_binds;
......
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