Conditional structures: Difference between revisions
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===Other short-circuiting operators===
<tt>and</tt>, <tt>or</tt>, <tt>&&</tt>, <tt>||</tt> and <tt>//</tt> work as in Perl 5.
=={{header|Phix}}==
===if===
<lang Phix>if name="Pete" then
-- do something
elsif age>50 then
-- do something
elsif age<20 then
-- do something
else
-- do something
end if</lang>
There is no limit to the number of elsif clauses, including 0. The else clause is also optional,
whereas the end if is always mandatory (which avoids any dangling else problems). All conditional
expressions are short-circuited.
===iff===
<lang Phix>var = iff(flag?true_expr:false_expr)</lang>
In an iff() expression, only one of true_expr or false_expr will be evaluated, not both.
Phix has some rudimentary support of preprocessor idef statments, but their use is discouraged
(since they are quite unnecessary in Phix, I might add).
===switch===
<lang Phix>switch v [with fallthrough] do
case 1,2:
-- do something
case 3 then
-- do something
fallthrough
case 4:
-- do something
break
default:
-- do something
end switch</lang>
By default there is no fallthough on switch clauses, however you can add a directive, and you can
override individual clauses with explicit fallthough or break statements. There is no need to have
break between cases when it is the default. You can use either : or then on case clauses. The else
keyword can be used instead of "default", and behaves identically. It can also be placed anywhere,
even first, or completely omitted.
The compiler will automatically construct either a jump table or daisy-chained cmp/jmp chains from
either if-constructs or switch-statements, leaving the programmer free to choose whichever shows
the intent clearest, without having to worry about performance implications.
===ilASM===
Inline assembly, in the form of #ilASM{} constructs, should you be brave or desperate enough to
use them, also have some conditional guards for cross-platform support
<lang Phix>#ilASM{
[32]
mov eax,[var]
[64]
mov rax,[var]
[PE32]
push eax -- uExitCode
call "kernel32.dll","ExitProcess"
[PE64]
mov rcx,rax -- uExitCode
call "kernel32.dll","ExitProcess"
[ELF32]
mov ebx,eax -- error_code (p1)
mov eax,1 -- sys_exit(ebx=int error_code)
int 0x80
-- xor ebx,ebx -- (common requirement after int 0x80)
[ELF64]
mov rdi,rax -- error_code (p1)
mov rax,60 -- sys_exit(rdi=int error_code)
syscall
[]
}</lang>
=={{header|PHL}}==
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