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Date: Sat, 09 Sep 2017 13:21:03 +0200
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Subject: [RFC] Match expression
From: ilija.tovilo@me.com

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Hi everybody=21

Has this idea been discussed before=3F

I find myself writing switch statements in PHP quite rarely. This has a f=
ew reasons:

1. It doesn=E2=80=99t have a =22strict=5Ftypes=E2=80=9D version
2. It is quite verbose (lots of breaks)
3. It is a statement rather than an expression

Often, if / elseif statements turn out to be shorter, safer and easier to=
 read than the switch statement.
What I=E2=80=99d really love is something like a match expression:

=60=60=60
=24r =3D match (=24x) =7B
=C2=A0 =C2=A0 1: =E2=80=98Tiny=E2=80=99;
=C2=A0 =C2=A0 <=3D 10: =E2=80=98Small=E2=80=99;
=C2=A0 =C2=A0 <=3D 20: =E2=80=98Medium=E2=80=99;
=C2=A0 =C2=A0 <=3D 30: =E2=80=98Large=E2=80=99;
=C2=A0 =C2=A0 range(31, 100): =E2=80=98Enormous=E2=80=99; // Equivalent t=
o =60in=5Farray(=24x, range(31, 100), true)=60
=C2=A0 =C2=A0 instanceof =46oo, instanceof Bar: =E2=80=98What=3F=E2=80=99=
;
=C2=A0 =C2=A0 default: =E2=80=98Unknown=E2=80=99;
=7D;
=60=60=60

These are the main differences compared to a traditional =60switch=60 sta=
tement:

- The whole =60match=60 is an expression, the result of the executed =60c=
ase=60 is implicitly returned
- It allows pattern matching, not just =60=3D=3D=60 comparison, =60=3D=3D=
=3D=60 is the default
- It does no implicit type conversion, thus no unexpected results when mi=
xing strings and numbers
- Each case has an implicit =60break=60
=C2=A0 =C2=A0 - Where you=E2=80=99d previously use two =60case=60s withou=
t a break, you now combine conditions using a comma

One downside, since PHP doesn=E2=80=99t implicitly return the last statem=
ent as some languages do there=E2=80=99s no obvious way to do multi-state=
ment cases.

I assume that some people will not be so happy about having to switch-lik=
e constructs. IMO the implicit type conversion is the biggest issue here.=
 Maybe we could offer a solution for this one at least.

Just some random thoughts.

Regards



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