Summary
Matches patt n characters behind the current position, consuming no input
Prototype
lpeg.B (patt, n)
Description
Returns a pattern that matches only if the input string matches patt starting n positions behind the current position. (The default value for n is 1.) If the current position is less than or equal to n, this pattern fails.
Like the "and predicate", this pattern never consumes any input, independently of success or failure, and it never produces any capture.
The pattern patt cannot contain any open reference to grammar rules (see grammars).
(This is an experimental feature. There is a good chance it will change in future versions.)
See Also ...
Lua functions
lpeg.C - Creates a simple capture
lpeg.Carg - Creates an argument capture
lpeg.Cb - Creates a back capture
lpeg.Cc - Creates a constant capture
lpeg.Cf - Creates a fold capture
lpeg.Cg - Creates a group capture
lpeg.Cmt - Creates a match-time capture
lpeg.Cp - Creates a position capture
lpeg.Cs - Creates a substitution capture
lpeg.Ct - Creates a table capture
lpeg.locale - Returns a table of patterns matching the current locale
lpeg.match - Matches a pattern against a string
lpeg.P - Converts a value into a pattern
lpeg.print - Outputs debugging information to stdout
lpeg.R - Returns a pattern that matches a range of characters
lpeg.S - Returns a pattern that matches a set of characters
lpeg.setmaxstack - Sets the maximum size for the backtrack stack
lpeg.type - Tests if a value is a pattern
lpeg.V - Creates a non-terminal variable for a grammar
lpeg.version - Returns the LPeg version
Topics
Lua bc (big number) functions
Lua bit manipulation functions
Lua LPEG library
Lua package functions
Lua PCRE regular expression functions
Lua script extensions
Lua string functions
Lua syntax
Lua table functions
Lua utilities
Regular Expressions
Scripting
Scripting callbacks - plugins
(Help topic: lua=lpeg.B)