PmWiki | Cookbook / ConditionalExtensions

Summary: A Conditional Markup extension for PmWiki 2.x

Version: 20061028

Status: Stable

Prerequisites: pmwiki-2.0.beta36

Maintainer: Dfaure

Categories: Markup

Question answered by this recipe

I've found the ConditionalMarkup very powerful, but how do I handle more complex expressions involving string/number comparisons, pattern/pagename matching and/or several simultaneous conditions ?

Description

Download extendcond.php Δ, save it in the cookbook directory and add: include_once("$FarmD/cookbook/extendcond.php"); to your local configuration file.

Notes and Comments

The recipe script provides extras conditional markup verbs to handle regular boolean expressions and string/number comparisons.

String/Number comparisons

(:if eq VALUE1 VALUE2:)
(:if lt VALUE1 VALUE2:)
(:if le VALUE1 VALUE2:)
(:if gt VALUE1 VALUE2:)
(:if ge VALUE1 VALUE2:)

All these conditions compares two string/number values.

They may be either literal or variable values as in: (:if eq {$Author} Dfaure:)

Strings containing spaces may be enclosed between quotes.

condition	meaning
`eq`	synonym for `equal`
`lt`	less than
`le`	less or equal than
`gt`	greater than
`ge`	greater or equal than

All these condition verbs may be given with a trailing 'i' as in eqi, lti,... to do case-insensitives comparisons.

Pattern/Pagename matching

`(:if regmatch REG_EXPRESSION VALUE:)`	True if the value matches the regular expression.
`(:if matchname NAME_SPEC PAGENAME:)`	True if the given pagename/groupname match the wildcard placeholder specification.
`(:if matchgroup GROUP_SPEC GROUPNAME:)`

Boolean expressions

The boolean expressions extension defined by this recipe has been integrated into PmWiki core since v2.1.0beta33: The related recipe code part does not interfere with the latest core implementation.

Following forms are equivalents:

(:if expr BOOLEAN_EXPRESSION :)
(:if [ BOOLEAN_EXPRESSION ] :)
(:if ( BOOLEAN_EXPRESSION ) :)

The "expr" condition take sub-conditions expressions combined with regular PHP boolean operators and brackets, and let PHP evaluate them to get the result.

Example	Name	Result
`A and B`	And	TRUE if both A and B are TRUE.
`A or B`	Or	TRUE if either A or B is TRUE.
`A xor B`	Xor	TRUE if either A or B is TRUE, but not both.
`! A`	Not	TRUE if A is not TRUE.
`A && B`	And	TRUE if both A and B are TRUE.
`A \|\| B`	Or	TRUE if either A or B is TRUE.

With A and B being either regular conditions (see ConditionalMarkup) or bracketed boolean expressions of regular conditions.

Warnings

Spaces around operators and brackets are required.
No specific feedback is given for syntaxic errors or unbalanced brackets.

Sample

With the code below:

(:if expr auth admin || auth attr || auth edit :)
[[Logout -> {$Name}?action=logout]] %green%{$Author}%%
(:if:)

you get a logout link followed by the current author name available only when authentified with higher than 'read' right.

Contributors

Release Notes

2005-02-28 Initial proof-of-concept release.
2005-04-20 Updated to a more reliable/usual syntax.
2005-05-03 Following a Pm's suggestion, spaces around operators are now mandatory to allow exclamation marks and parenthesis in regular conditions terms.
2005-09-14 Removed extraneous undocumented "Properties" features to its own recipe.
2005-09-19 Fixed a security issue (thanks to Pm and M.Fick). Added alternates syntax forms and equality condition.
2006-03-02 Revamped equality condition to more general string/numbers comparisons. Updated licensing terms.
2006-06-20 Added partial string matches with regular expressions.
2006-10-28 Added RecipeInfo data. Added pagename wildcard matching.

Sandbox

Some boolean tables:

`A`	`B`	`C`	`A or ( B and C )`	`A and ( ! B or C )`
F	F	F	F	F
F	F	T	F	F
F	T	F	F	F
F	T	T	T	F
T	F	F	T	T
T	F	T	T	T
T	T	F	T	F
T	T	T	T	T

`A`	`B`	`( A && ! B ) \|\| ( ! A && B )`	`A xor B`
F	F	F	F
F	T	T	T
T	F	T	T
T	T	F	F

Comments

In my wiki this:

(:if ( ! {$:Val} ) :)false(:else:)true(:if:)

returns true.

Val is unset, so why isn't it false? But even by writing (:Val::), (:Val:0:), or (:Val:false:) it keeps returning true.

Nick - 2007.12.19

ps. is there no way to nest conditions? maybe with some cookbook recipe I haven't discovered yet?

It's not the same as conditional markup, but conditional markup expressions are possible via WikiSh.php

Peter Bowers March 23, 2008, at 06:12 AM

ConditionalExtensions