Modifying A Line With An Error

When a line is modified that contains an error, the highlighted error can be shifted around or changed in size.  This can make the error message no longer applicable, so the highlighted error should be removed.  Upon the cursor leaving the line, the line will be rechecked for errors.  A check for this situation was added to the document change slot of the edit box class when a single line is changed.  No action was taken for single line changes.

When a single line is modified, the errors lists is searched its line number.  If the line contains an error, but the modification occurred after the error, no further action is taken.  If the cursor and the error are at the end of the line, or the cursor is within the error, the error is removed from the error list.  If the cursor is before the error, the column of the error is moved by the net change (number of characters added less the number removed).

The update errors slot is called to update the display.  A cursor changed signal is also emitted so that the error message on the status line is removed when the error is removed.  This didn't always occur because the cursor is not always moved when the document is changed (for example, when characters are deleted).  New move error column functions were added to the error list and error item classes to support the shifting of errors.

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