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author | Matej Kosik <m4tej.kosik@gmail.com> | 2016-08-30 11:47:35 +0200 |
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committer | Matej Kosik <m4tej.kosik@gmail.com> | 2016-08-30 11:47:35 +0200 |
commit | 4f21c45748816c9e0cd4f93fa6f6d167e9757f81 (patch) | |
tree | f22bde63a6522883782ada4c40fa6b5c1ff1cc4c /pretyping/arguments_renaming.ml | |
parent | 2ff6d31c7a6011b26dfa7f0b2bb593b356833058 (diff) |
CLEANUP: switching from "right-to-left" to "left-to-right" function composition operator.
Short story:
This pull-request:
(1) removes the definition of the "right-to-left" function composition operator
(2) adds the definition of the "left-to-right" function composition operator
(3) rewrites the code relying on "right-to-left" function composition to rely on "left-to-right" function composition operator instead.
Long story:
In mathematics, function composition is traditionally denoted with ∘ operator.
Ocaml standard library does not provide analogous operator under any name.
Batteries Included provides provides two alternatives:
_ % _
and
_ %> _
The first operator one corresponds to the classical ∘ operator routinely used in mathematics.
I.e.:
(f4 % f3 % f2 % f1) x ≜ (f4 ∘ f3 ∘ f2 ∘ f1) x
We can call it "right-to-left" composition because:
- the function we write as first (f4) will be called as last
- and the function write as last (f1) will be called as first.
The meaning of the second operator is this:
(f1 %> f2 %> f3 %> f4) x ≜ (f4 ∘ f3 ∘ f2 ∘ f1) x
We can call it "left-to-right" composition because:
- the function we write as first (f1) will be called first
- and the function we write as last (f4) will be called last
That is, the functions are written in the same order in which we write and read them.
I think that it makes sense to prefer the "left-to-right" variant because
it enables us to write functions in the same order in which they will be actually called
and it thus better fits our culture
(we read/write from left to right).
Diffstat (limited to 'pretyping/arguments_renaming.ml')
-rw-r--r-- | pretyping/arguments_renaming.ml | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/pretyping/arguments_renaming.ml b/pretyping/arguments_renaming.ml index ff6b33c49..077ee4e15 100644 --- a/pretyping/arguments_renaming.ml +++ b/pretyping/arguments_renaming.ml @@ -50,7 +50,7 @@ let discharge_rename_args = function (try let vars,_,_ = section_segment_of_reference c in let c' = pop_global_reference c in - let var_names = List.map (Name.mk_name % NamedDecl.get_id % fst) vars in + let var_names = List.map (fst %> NamedDecl.get_id %> Name.mk_name) vars in let names' = List.map (fun l -> var_names @ l) names in Some (ReqGlobal (c', names), (c', names')) with Not_found -> Some req) |