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Top Forums UNIX for Advanced & Expert Users When is a _function_ not a _function_? Post 302832031 by wisecracker on Friday 12th of July 2013 02:00:34 PM
Old 07-12-2013
When is a _function_ not a _function_?

For a starter I know the braces are NOT in the code...

Consider these code snippets:-
Code:
#!/bin/bash --posix
x=0
somefunction()
if [ $x = 0 ]
then
	echo "I am here."
fi
# somefunction





#!/bin/bash --posix
x=0
somefunction()
if [ $x = 0 ]
then
	echo "I am here."
fi
somefunction





#!/bin/bash --posix
x=0
somefunction()
echo "Why does this crash?"
if [ $x = 0 ]
then
	echo "I am here."
fi
somefunction

Now using OSX 10.7.5 and bash here is the result:-
Code:
Last login: Fri Jul 12 18:41:45 on ttys000
AMIGA:barrywalker~> ./func.sh
AMIGA:barrywalker~> ./func.sh
I am here.
AMIGA:barrywalker~> ./func.sh
./func.sh: line 4: syntax error near unexpected token `echo'
./func.sh: line 4: `echo "Why does this crash?"'
AMIGA:barrywalker~> _

Why do the first two snippets work as predicted, (although without the braces), yet the third crashes out with the error report?
What is going on?

Can someone explain what is going on?

Many thanks...
 
ECHO(3) 								 1								   ECHO(3)

echo - Output one or more strings

SYNOPSIS
void echo (string $arg1, [string $...]) DESCRIPTION
Outputs all parameters. echo is not actually a function (it is a language construct), so you are not required to use parentheses with it. echo (unlike some other language constructs) does not behave like a function, so it cannot always be used in the context of a function. Additionally, if you want to pass more than one parameter to echo, the parameters must not be enclosed within parentheses. echo also has a shortcut syntax, where you can immediately follow the opening tag with an equals sign. Prior to PHP 5.4.0, this short syn- tax only works with the short_open_tag configuration setting enabled. I have <?=$foo?> foo. PARAMETERS
o $arg1 - The parameter to output. o $... - RETURN VALUES
No value is returned. EXAMPLES
Example #1 echo examples <?php echo "Hello World"; echo "This spans multiple lines. The newlines will be output as well"; echo "This spans multiple lines. The newlines will be output as well."; echo "Escaping characters is done "Like this"."; // You can use variables inside of an echo statement $foo = "foobar"; $bar = "barbaz"; echo "foo is $foo"; // foo is foobar // You can also use arrays $baz = array("value" => "foo"); echo "this is {$baz['value']} !"; // this is foo ! // Using single quotes will print the variable name, not the value echo 'foo is $foo'; // foo is $foo // If you are not using any other characters, you can just echo variables echo $foo; // foobar echo $foo,$bar; // foobarbarbaz // Some people prefer passing multiple parameters to echo over concatenation. echo 'This ', 'string ', 'was ', 'made ', 'with multiple parameters.', chr(10); echo 'This ' . 'string ' . 'was ' . 'made ' . 'with concatenation.' . " "; echo <<<END This uses the "here document" syntax to output multiple lines with $variable interpolation. Note that the here document terminator must appear on a line with just a semicolon. no extra whitespace! END; // Because echo does not behave like a function, the following code is invalid. ($some_var) ? echo 'true' : echo 'false'; // However, the following examples will work: ($some_var) ? print 'true' : print 'false'; // print is also a construct, but // it behaves like a function, so // it may be used in this context. echo $some_var ? 'true': 'false'; // changing the statement around ?> NOTES
Note Because this is a language construct and not a function, it cannot be called using variable functions. SEE ALSO
print(3), printf(3), flush(3), Heredoc syntax. PHP Documentation Group ECHO(3)
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