[Lazarus] Semicolon checking

[DougC]

I'm not going to kick you, Mark, as your comments are spot on. 



What I think wold be very helpful to the FPC community is a warning that is issued when a semi-colon is immediately followed by a "begin" as that is an unusual construct and, as shown in the example here, an indicator of a likely mistake.



Doug C.





---- On Mon, 16 Jan 2017 03:27:25 -0500 Mark Morgan Lloyd via Lazarus <lazarus at lists.lazarus-ide.org> wrote ----




On 16/01/17 07:30, Lars via Lazarus wrote:

> On Sun, January 15, 2017 3:30 pm, Vojtěch Čihák via Lazarus wrote:> Hello, has Lazarus (CodeTools) or FPC some checking for empty commands? I> accidentally did this stupid mistake: > if ... then begin>> end else;> begin> ...> exit;> end;>

> Yikes! I think you just discovered a bug in the pascal language itselfthat was not thought of... as when using a text editor it's easy to leavea semi colon laying around by accident some times.

> I wonder if Oberon solves this issue, or semi-colon-less languages haveany advantage. If you remove the begin from a language (Wirth did in hislater languages) you get rid of some issues.-- _______________________________________________Lazarus mailing listLazarus at lists.lazarus-ide.orghttp://lists.lazarus-ide.org/listinfo/lazarus



It's one of a number of known nasties in the language definition. This 

is controversial, but Pascal was defined with ; being a /separator/ not 

a /terminator/, so strictly a semicolon is not needed before end else 

until etc. and in my experience only using it where necessary is a good 

habit to get into ( ;until was a syntax error in at least some versions 

of Turbo Pascal).



One other thing that helps in a very small way is to use 

case-otherwise-end rather than case-else-end, since it reduces the 

number of ambiguities.



Apart from that Wirth deserves no credit at all for leaving the 

dangling-else ambiguity in Pascal when it had been recognised and 

eliminated in ALGOL-68.



I expect to get kicked for all of the above. They are my opinions only, 

and might not be aligned with e.g. the coding style expected in patches 

submitted to the FPC or Lazarus projects.



-- 

Mark Morgan Lloyd

markMLl .AT. telemetry.co .DOT. uk



[Opinions above are the author's, not those of his employers or colleagues]

-- 

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