FRONTIER(5)

Table of Contents

• Name
• Synopsis
• Description
• Example
• See Also

Name

frontier

returns the original specification string for any node

Lfrontier

returns the original specification string for any list of nodes

Synopsis

STRING frontier(any)
ANY any;
STRING Lfrontier(any)
ANY any;

Description

These two components of the run-time library are functions that return the original text from the specification file that, when parsed, created a node or list of nodes in the parse tree. This text is called the frontier of a node or node list.

frontier returns the frontier of node any. Lfrontier returns the frontier of node any and all nodes that follow it in a list of nodes.

Example

If the grammar section were:
input: ( fname+ num )
fname: <[a-zA-Z]+>
num: <[0-9]+>
and the specification file contained:
one two three 7
then the following expressions would return the values given:

frontier(top)

returns «one two three 7"

frontier(num(top))

returns «7"

frontier(fname(top))

returns «one"

Lfrontier(fname(top))

returns «one two three"

Lfrontier(next(fname(top)))

returns «two three"

See Also

BEGLINE(5)
LIST(5)
TOKEN(5)