Module parser/rules/inline/expr

Parses Wikidot's inline expression and conditional block syntax:

• [[#expr expression]] -- evaluate a mathematical expression and display the result
• [[#if value | then | else]] -- simple truthy/falsy conditional
• [[#ifexpr expression | then | else]] -- expression-based conditional

All three forms begin with [[# followed by the keyword. The # prefix distinguishes these from regular [[block]] syntax.

[[#if]] treats its condition as a string and considers these values falsy: "false", "null", "", "0". Everything else is truthy.

[[#ifexpr]] evaluates its condition as a mathematical expression and treats the numeric result as falsy when zero.

Both conditional forms support an optional else branch: when only one pipe-separated branch is provided, the else branch is empty.

Expressions are limited to 256 characters (after trimming) to prevent abuse.

The pipe (|) delimiter is depth-aware: pipes inside nested [[]] or [[[]]] blocks are not treated as branch separators.