labels - text descriptions for SFS items


The labels data file is used by various programs to determine a textual description of a data item from its history field (and the history fields of other items in a file). Access to the file is usually made through the labelling support routines, see label(SFS3).

The file is initially generated with text editor, and then processed using the utility prolab(SFS1) to index it for fast access. This processed file can then be subsequently amended and re-processed.

The file consists of lines in a fixed format:

    <match expression>:<text description>:(<short code>{:<short code>})

"match expression" is a string match expression that is matched against the expanded history field of the item being processed using histmatch(SFS3). (The "expanded" history field is generated by recursively substituting item numbers for history fields of referred-to items). The string match expressions may contain sub-matched parameters "%0" and "%1" which are recursively searched to extract text descriptions for components of the expanded history string.

"text description" is the text description of the item history. Text descriptions of sub-matches are substituted in the text description at the position of "%s" in the string (re: printf). If text descriptions are not found for sub-matches, then the sub-match itself is substituted.

"short code" Each line can end in 1 or more "short codes" that may be used as shorthand for the string match expression with the routine itspec(SFS3). Lines do not need to have any short codes assigned to them, and short codes may be duplicated across lines.


Example lines from the labels file might be:

	inwd(*):input speech:SPnat:
	agc(%0):agc'd %s:SPagc:LXagc:
	ilslpfilt(%0;freq=%1):%s lo-pass @ %s:




2.0 - Mark Huckvale


itspec(SFS3) label(SFS3) histmatch(SFS3)
Fri Jul 09 14:54:51 2004