tcl grammar

Shihying Chen

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Dec 19, 1998, 3:00:00 AM12/19/98

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Is there a grammar of Tcl?
SY

Paul Duffin

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Dec 21, 1998, 3:00:00 AM12/21/98

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Shihying Chen wrote:
>
> Is there a grammar of Tcl?
> SY

Probably not in the sense that you mean (BNF). Look at the Tcl man
page for a description of the syntax.

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Paul Duffin
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Cameron Laird

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Dec 21, 1998, 3:00:00 AM12/21/98

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In article <367B4967...@sbchm1.sunysb.edu>,

Shihying Chen <sc...@sbchm1.sunysb.edu> wrote:
>Is there a grammar of Tcl?
>SY
>

<URL:http://www.scriptics.com/man/tcl8.0/TclCmd/Tcl.htm>
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Shih-Ying Chen

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Dec 21, 1998, 3:00:00 AM12/21/98

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Paul Duffin wrote:

> Shihying Chen wrote:
> >
> > Is there a grammar of Tcl?
> > SY
>

> Probably not in the sense that you mean (BNF). Look at the Tcl man
> page for a description of the syntax.
>

Sorry for the confusion. Yes, I meant BNF notation.
I would like to build a tool to parse a tcl program before I run it.
With BNF notation , I can use Bison (or yacc) to build the tool.
By the way described in the tcl manual, it's a little troublesome. :)
Maybe it's fun to tranform those syntax into BNF.
SY

Paul Duffin

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Dec 22, 1998, 3:00:00 AM12/22/98

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Tcl's grammar is defined by the commands that are available and it is
possible for a program to change the built in commands and create other
functions which in other languages would need to be builtin.

lvi...@cas.org

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Dec 23, 1998, 3:00:00 AM12/23/98

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According to Shih-Ying Chen <sc...@sbchm1.chem.sunysb.edu>:
:Sorry for the confusion. Yes, I meant BNF notation.

:I would like to build a tool to parse a tcl program before I run it.
:With BNF notation , I can use Bison (or yacc) to build the tool.
:By the way described in the tcl manual, it's a little troublesome. :)
:Maybe it's fun to tranform those syntax into BNF.

The want

<URL: http://www.purl.org/NET/Tcl-FAQ/part3.html>:

From: -XI- Where can I get these packages?
Subject: -G- BNF style notation for Tcl

<URL: mailto:tb...@CS2.cc.lehigh.edu> (TERRENCE MONROE BRANNON) in July of 1993,
posted some yacc code for a tcl-to-c parser. This, along with Adam Sah's Tcl
compiler, are a couple of sources with which folk could start.
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<*> O- <URL: http://www.purl.org/NET/lvirden/>
Unless explicitly stated to the contrary, nothing in this posting
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Victor Wagner

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Dec 26, 1998, 3:00:00 AM12/26/98

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Shihying Chen (sc...@sbchm1.sunysb.edu) wrote:
: Is there a grammar of Tcl?
: SY

No. And it is very important thing to understand.

Tcl is not based on conventional LALR parser. It rather have very short
list of basic substitution rules (rather lexical level then grammar
level) described in Tcl(n) man page and set of command, which is
extensible. Anything in Tcl (inculding for, if and such) is just a
command with list of args.

So, any attempt to create yacc-like grammar for Tcl would probably
end-up in incomplete, if not incompatible parser.
Really, there should be Tcl interpreter, to understand how command set
changes upon proc and rename invocations, as well as on package require
and package forget. And don't forget autoloading and eval.
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