nextfield
nextfield |
Purpose
Advance to next field in a structured text string.
Synopsis
function nextfield(txt:text,start:integer,trim:boolean):boolean
function nextfield(txt:text):boolean
function nextfield(txt:text,pctx:parsectx):boolean
Arguments
txt
|
A
text object
|
pctx
|
A parser context
|
start
|
Starting position in the text
|
trim
|
Whether to skip blank characters around separators
|
Return value
true if more data can be parsed.
Example
The following function returns the list of records of a text string using comma as the field separator character:
function split(t:text):list of text declarations pctx:parsectx end-declarations pctx.sepchar:=44 ! ',' while(nextfield(t,pctx)) do returned+=[parsetext(t,pctx)] end-do end-function
Further information
1. When
start is
0, this routine saves the position of the first character of the text string in the control parameter
sys_endparse and returns
true.
2. When
start is greater than
0 and the character located at position
start is the separator character
sys_sepchar, the position
start+1 is saved in control parameter
sys_endparse and
true is returned. In all other cases
false is returned.
3. This function returns
false if the provided text
txt is empty or the starting position
start is not valid.
4. If argument
trim is
true, blank characters are skipped before and after the separator character. The provided value is saved in parameter
sys_trim when
start is
0.
5. In the second form of the routine, parameters
sys_endparse and
sys_trim are used as default values for arguments
start and
trim.
6. The version using a parser context works with the information contained in this context instead of the global parameters (see Section
The type parsectx).
Related topics
Module