«if», «else» and «while» are keywords part of "if" statements and "while" statements. Flow control statements don't take semicolons. 

while ( COND ) BLOCK
if ( COND ) BLOCK

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The «if» and «while» keywords are also found in statement modifiers. Statements with statement modifiers do take a semicolon.[1] 

EXPR while COND;
EXPR if COND;

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eval and map are "functions" (named operators). Function calls do no take semicolons. 

if ( !eval { f() } ) { ... }

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But they may be found in statements which do use a semicolon. 
my $x = eval { f() }
   or ...;

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This includes simple statements.[1] These are statements that consist of nothing but an expression. 

EXPR;

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The statement you gave is an example of a simple statement, and so is the «or»-using statement above.

C, C++, C#, JavaScript and Java all work this way.

  1. The semicolon can be omitted if it terminates the last statement of a block or file.

Updated to elaborate.

In reply to Re: why does Perl eval have a strange terminator? by ikegami
in thread why does Perl eval have a strange terminator? by misterperl

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