BBCode


BBCode is a lightweight markup language used to format messages in many Internet forum software. It was first introduced in 1998. The available "tags" of BBCode are usually indicated by square brackets surrounding a keyword, and are parsed before being translated into HTML.
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Implementation

BBCode is typically implemented by applying a series of regular expression string-replace operations upon the input. Because regular expressions are limited in analyzing the structure of text input, this has the artifact that any non-hierarchical BBCode input will be transformed into invalid non-hierarchical HTML without error.
Applying traditional parsing techniques is made difficult by ambiguities in the markup, such as in, where the input can either be interpreted as "text" quoted from someone called, or the bolded text "text" surrounded by and, i.e. .