[R] simple if...else causes syntax error

[Peter Dalgaard]

Gabor Grothendieck <ggrothendieck at myway.com> writes:

> Jan T. Kim <jtk <at> cmp.uea.ac.uk> writes:

> : Out of personal interest: Does anyone here know why the R parser was
> : designed this way? Personally, I have been coding in R for years in the
> : belief that newline is whitespace, and never even noticed any problems
> : because all my ifs with elses were within functions and thus enclosed
> : in curly braces.
> : 
> 
> If it did not work that way it would require console lookahead.  That is 
> it would not know that the if statement was finished and would have
> to wait for the following statement to be completely typed in before
> it could process the if.  The way it works now the if statement can
> be processed immediately.

Or put differently, the language designers were not quite aware of the
reason that other command-line languages tend to use explicit
construct terminators like "endif" or "fi".... (I think that is almost
a quote from one of the prominent language experts inside R core, but
I can't pinpoint the details.)

-- 
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