[plt-scheme] [OT] grateful for PLT Check Syntax

From: Geoffrey S. Knauth (geoff at knauth.org)
Date: Fri Oct 9 15:48:31 EDT 2009

On Oct 9, 2009, at 15:34, Chognkai Zhu wrote:

> Sorry for telling that, but that story has nothing to do with PLT's  
> Check Syntax. For nearly all languages, reference to an undefined  
> variable is a compile time error. But this is not true for Computer  
> Algebra Systems(CAS). Even with no values bind to variable `x', a  
> CAS should still reduce `x+x+x' to `3x', which implies reference to  
> an undefined variable is not an error. But CAS do have their merits.

Yes, you're right.  But there was another part of the story that made  
me think of Check Syntax.  He had other code that had variable names s  
and ss.  In one place, he had forgotten an s, and ss became s.  Check  
Syntax would have drawn arrows helping him see that mistake.

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