4glworks reference: Pick lists

Pick lists all have in common behaviour a capabilities, and have been differentiated only on the number of columns they display (description, or code and description), and the number of entries returned (single or multiple).
Common characteristics are:

Ability to gather data to display from
- queries (set tbl to null)
- multiple files (set tbl to "file", and place a semicolon separated list of files in cond)
- pipes (set tbl to "pipe")
Handle comments (marked by hashes)
Return data immediately, if only one row is available
Position the cursor on the closest entry to user specifications on invocation (set buf to the string to be matched)
Search entries by starting character
Being implemented on text variables, have no limitation in the number of entries they can handle

The available flavours follow:

multi_desc
multi_help
uni_desc
uni_help

multi_desc

file	iml2h.4gl
declaration	function multi_desc(tbl, cond, ln, sep, quotes, buf) define tbl char(4), #source cond char(300), #statement, file list or pipe ln smallint, #output buffer length sep char(1), #multiple entry separator char quotes char(2), #start and end quote buf char(8) #initial match
returns	`d`, char(80), selected entries
purpose	single field, multiple choice pick list
example	none
notes	the size ot the rsturn buffer will be kept within `ln` chars it is possible to specify how multiple entries should be separated. the default separator is a whitespace. entries returned can optionally be surrounded by quotes. if `quotes` contains multiple characters, the first is used as the opening quote, and the second as the closing.

multi_help

file	imlth.4gl
declaration	function multi_help(tbl, cond, ln, sep, quotes, buf) define tbl char(4), #source cond char(300), #statement, file list or pipe ln smallint, #output buffer length sep char(1), #multiple entry separator char quotes char(2), #start and end quote buf char(8) #initial match
returns	`d`, char(80), selected entries
purpose	dual field, multiple choice pick list
example	none
notes	the size ot the rsturn buffer will be kept within `ln` chars it is possible to specify how multiple entries should be separated. the default separator is a whitespace. entries returned can optionally be surrounded by quotes. if `quotes` contains multiple characters, the first is used as the opening quote, and the second as the closing.

uni_desc

file	iun2h.4gl
declaration	function uni_desc(tbl, cond, buf) define tbl char(4), #source cond char(300), #statement, file list or pipe buf char(8) #initial match
returns	`d`, char(80), selected entry
purpose	single field, single choice pick list
example	none
notes	none

uni_help

file	iunih.4gl
declaration	function uni_help(tbl, cond, insnew, buf) define tbl char(4), #source cond char(300), #statement, file list or pipe insnew integer, #true if insertion of new rows allowed buf char(8) #initial match
returns	`c`, char(8), selected entry value `d`, char(80), selected entry description
purpose	dual field, single choice pick list
example	none
notes	none