ProvideX V8.20 > Language Reference > 2. Directives

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Format 11: Clear

GRID CLEAR ctl_id,col,row[,width,height][,ERR=stmtref]

Use the GRID CLEAR format to clear or reset the contents of a range of cells to the

default (empty). You can clear a column or a row or both.

Reminder: If you use zero (0) as your value for both column and row, ProvideX

interprets that as all columns and rows, respectively and will clear the entire grid.

Format 12: Read First Cell

GRID READ ctl_id,col,row,var$,eom$[,ERR=stmtref]

Use var$ in the GRID READ format to receive the modified cell address and value of the

first selected cell. If the cell doesn't exist, an Error #2: END-OF-FILE on read or

File full on write. If there is more to read, the CTL event is re-posted.

The eom$ string tells you which input sequence ended the message (e.g., $0D$ for

the Enter key).

GRID READ directive must include both column and row addresses. ProvideX returns

a queue of cells that have been changed and generates an additional CTL event after a

read to ensure that no events are lost. There can be a problem due to potential race

conditions when the host is unable to keep up with the user input. To circumvent this,

ProvideX returns Error #2: END-OF-FILE on read or File full on write

if the queue is empty

Note: Under NOMADS, the read is automatic and should not be done by your

application. The data read is placed in the standard input variable with

control_name.row and control_name.col containing the associated cell

information.

Format 13: Read Next

GRID READ NEXT ctl_id,col,row,var$,eom$[,ERR=stmtref]

Use the string var$ in the GRID READ NEXT format to receive the modified cell

address and value of the next (not first) selected cell. If this cell doesn't exist,

ProvideX returns an Error #2: END-OF-FILE on read or File full on write. If

there is more to read, no CTL event is re-posted. The CTL value is posted when

another cell is changed. The eom$ string tells you what input sequence ended the

message (e.g., $0D$ for the Enter key)

Formats 14, 15, 16, 17: Select Read/Reset

Use the following formats to select ranges of cells to READ or to RESET (to remove cells

from the SELECT state). GRID SELECT can be used to control cell selection. (When you

SELECT a range of cells, the given cells are added to the list of selected cells.)