Peter Harpending
68 lines
1.8 KiB
Erlang
68 lines
1.8 KiB
Erlang
-spec mktree(Signal) -> Tree when
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Signal :: gsc:signal(),
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Tree :: gsc_ntree:ntree().
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% @doc make into a tree
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mktree(Sig) ->
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Tree0 = gsc_ntree:nstem(vtokens, Sig),
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Tree1 = rerootl_tkstr("=>", Tree0),
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Tree2 = rerootl_tkstr("*", Tree1),
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Tree2.
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rerootl_tkstr(S, Tree0 = #ns{val = Root0}) ->
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Kids0 = gsc_ntree:deleaf0(Tree0),
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IsntS = fun(Tk) -> isnt_str(S, Tk) end,
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case lists:splitwith(IsntS, Kids0) of
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% found
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% input:
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% *s Root0
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% |
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% +-- .l Foo
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% +-- .l "=>"
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% +-- .l Bar
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% output:
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% *s "=>"
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% |
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% +-- *s Root0 -- .l Foo
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% +-- *s Root0 -- .l Bar
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{LHS1, [Tk0 | RHS1]} ->
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Root1 = Root0,
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LTree1 = gsc_ntree:releaf0(Root1, LHS1),
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RTree1 = rerootl_tkstr(S, gsc_ntree:releaf0(Root1, RHS1)),
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NewRoot0 = {op, Tk0},
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NewKids0 = [LTree1, RTree1],
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NewTree = gsc_ntree:releaf0(NewRoot0, NewKids0),
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NewTree;
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% not found, nothing to do
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{Kids0, []} ->
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Tree0
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end.
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%reroot_mapsto(Tree0 = #ns{val = Root0}) ->
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% Kids0 = gsc_ntree:deleaf0(Tree0),
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% IsntMapsto = fun(DL) -> isnt_str("=>", Tk) end,
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% case lists:splitwith(IsntMapsto, Kids0) of
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% % found
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% {LHS1, [Tk0 | RHS1]} ->
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% Root1 = Root0,
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% LTree1 = gsc_ntree:releaf0(Root1, LHS1),
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% RTree1 = reroot_mapsto(gsc_ntree:releaf0(Root1, RHS1)),
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% NewRoot0 = {op, Tk0},
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% NewKids0 = [LTree1, RTree1],
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% NewTree = gsc_ntree:releaf0(NewRoot0, NewKids0),
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% NewTree;
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% % nothing to do
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% {Kids0, []} ->
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% Tree0
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% end.
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isnt_str(X, Y) ->
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not is_str(X, Y).
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is_str(S, #tk{str = S}) -> true;
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is_str(_, _) -> false.
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