[Coco] INSTR question

[Allen Huffman]

> On Feb 9, 2017, at 3:40 PM, Salvador Garcia via Coco <coco at maltedmedia.com> wrote:
> 
> Hi,
> 
> It returns one because when the string to search is empty it returns the Start position. Since you've omitted this, it defaults to 1.
> 
> Try this:
> 
> PRINT INSTR(3,"1234567","")
> 
> This is what happened with VB6. It seems that this version of Basic carried over the behavior from earlier versions, including CoCo BASIC.
> 
> Have a look at the table under the section for Return Value:
> 
> https://msdn.microsoft.com/en-us/library/wybb344c(v=vs.84).aspx

Excellent. Thank you! That answers my question. Not a bug, but the way it works, which means it cannot be used without checking the string to be empty first, or doing a workaround like I just tried.

10 IF A$<>"" THEN LN=INSTR("ABCD",A$):ON LN

It's a pity, because ON x GOTO/GOSUB ignore the 0 value, so it it worked the same way, this could be done:

ON INSTR("ABC",INKEY$) GOTO 100,200,300

That's quite a bit faster than using a variable.

		-- A