package ppx_optional
Pattern matching on flat options
Install
Dune Dependency
Authors
Maintainers
Sources
ppx_optional-v0.9.0.tar.gz
sha256=0c4f54f42075c0f337bbf12e89d74c29cc68fa285ba3fc6fbf4a37c1c6f2aa4e
md5=84dfad9aa7e326f00d12101c8c353e2b
Description
A ppx rewriter that rewrites simple match statements with an if then else expression.
Published: 22 Mar 2017
README
title: ppx_optional - match statements for zero-alloc options parent: ../README.md
A ppx rewriter that rewrites simple match statements with an if then else expression.
Syntax
ppx_optional
rewrites the extension match%optional
in expressions. It requires that a module Optional_syntax
is in scope, and that it has is_none
and unchecked_value
values.
For instance:
match%optional e with
| None -> none_expression
| Some x -> some_expression
becomes:
if Optional_syntax.is_none e then begin
none_expression
end else begin
let x = Optional_syntax.unchecked_value e in
some_expression
end
Usage
This is normally used to safely access an optional value while avoiding allocation for immediate values (e.g. Immediate.{Char,Bool,Int}.Option
, Fixed.Option
, Price.Fixed.Option
, etc...).
Dependencies (6)
-
ocaml-migrate-parsetree
>= "0.4" & < "2.0.0"
-
ppx_metaquot
>= "v0.9" & < "v0.10"
-
ppx_driver
>= "v0.9" & < "v0.10"
-
ppx_core
>= "v0.9" & < "v0.10"
-
jbuilder
>= "1.0+beta4"
-
ocaml
>= "4.03.0"
Dev Dependencies
None
Used by (1)
-
ppx_jane
= "v0.9.0"
Conflicts
None
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