dcornutt@murphy.UUCP (Dave Cornutt) (01/07/88)
I have discovered something peculiar about csh variable substitution. Is
this a bug or am I doing something wrong? Watch this:
example 1:
% set xyz=qwert
% echo $xyz
qwert
% set xyz=${xyz}_123
% echo $xyz
qwert_123
%
example 2:
% set xy1z=qwert
% echo $xy1z
qwert
% set xy1z=${xy1z}_123
Variable syntax.
% echo $xy1z
qwert
%
Note that the only difference between these two examples is in the variable
name. After further experimenting, I discovered that the ${foo} form
seems to choke whenever the variable name has a digit in it; variable
names consisting solely of lower-case alphabetics always work. (I haven't
tried using other characters.) I tried quoting the string in various ways,
none of which made any difference. Has anyone ever seen this? Is it a bug,
or did I just get up too early?
The OS involved here is UTX/32, rev 2.0, which is BSD4.3 based. However,
I have gotten the same results on Sun 3.2, which is 4.2-based, so I think
it's generic to csh. Any hints?
---
Dave Cornutt, Gould Computer Systems, Ft. Lauderdale, FL
[Ignore header, mail to these addresses]
UUCP: ...!{sun,pur-ee,brl-bmd,uunet,bcopen,rb-dc1}!gould!dcornutt
or ...!{codas,mia,hrshcx}!novavax!gould!dcornutt
paths to codas: allegra,ucf-cs,peora,killer,burl,mtune,ufsvax2,flnexus,toynix
ARPA: dcornutt@gswd-vms.gould.com
"The opinions expressed herein are not necessarily those of my employer,
not necessarily mine, and probably not necessary."paul@devon.UUCP (Paul Sutcliffe Jr.) (01/10/88)
In article <826@murphy.UUCP> dcornutt@murphy.UUCP (Dave Cornutt) writes: +---------- | I have discovered something peculiar about csh variable substitution. Is | this a bug or am I doing something wrong? Watch this: | | % set xy1z=qwert | % echo $xy1z | qwert | % set xy1z=${xy1z}_123 | Variable syntax. | % echo $xy1z | qwert | | The OS involved here is UTX/32, rev 2.0, which is BSD4.3 based. However, | I have gotten the same results on Sun 3.2, which is 4.2-based, so I think | it's generic to csh. Any hints? +---------- I tried this same thing on the csh on Microsoft Xenix 3.0 (Xenix/68000 on a Tandy 16), and got the same results. Not having source, I cannot suggest what is causing this (or offer a fix), but I thought I mention this for those who can. - paul -- Paul Sutcliffe, Jr. UUCP (smart): paul@devon.UUCP UUCP (dumb): ...{rutgers,ihnp4,cbosgd}!bpa!vu-vlsi!devon!paul
hansen@mips.UUCP (Craig Hansen) (01/11/88)
In article <826@murphy.UUCP> dcornutt@murphy.UUCP (Dave Cornutt) writes: > I have discovered something peculiar about csh variable substitution. Is > this a bug or am I doing something wrong? You're doing something wrong. The correct syntax is: % set xy1z={$xy1z}_123 -- Craig Hansen Manager, Architecture Development MIPS Computer Systems, Inc. ...{ames,decwrl,prls}!mips!hansen or hansen@mips.com
jam@philabs.Philips.Com (John A. Murphy) (01/12/88)
In article <590@devon.UUCP> paul@devon.UUCP (Paul Sutcliffe Jr.) writes: >In article <826@murphy.UUCP> dcornutt@murphy.UUCP (Dave Cornutt) writes: >+---------- Instead of >| % set xy1z=${xy1z}_123 % set xy1z={$xy1z}_123 >| % echo $xy1z qwert_123 -- jam@philabs.uucp
schaefer@ogcvax.UUCP (Barton E. Schaefer) (01/12/88)
In article <mips.1269> hansen@mips.UUCP (Craig Hansen) writes: >In article <826@murphy.UUCP> dcornutt@murphy.UUCP (Dave Cornutt) writes: >> I have discovered something peculiar about csh variable substitution. Is >> this a bug or am I doing something wrong? > >You're doing something wrong. The correct syntax is: > >% set xy1z={$xy1z}_123 >-- >Craig Hansen Sorry, Craig, that syntax changes the meaning of the {} from "variable substitution" to "filename substitution" as in % set xy1z="one,two,three" % set xyz={$xy1z}_step % set xy1z one,two,three xyz (one_step two_step three_step) The syntax ${xy1z} SHOULD work, but it doesn't (confirmed here for Mt. Xinu 4.3 BSD csh as well). Does anyone happen to know why it fails? Does it have anything to do with ${1} being a synonym for $1 (and ${2} for $2 and so on)? -- Bart Schaefer CSNET: schaefer@cse.ogc.edu UUCP: ...{tektronix,verdix}!ogcvax!schaefer "A band of BIG, DUMB, LOUDMOUTHED, BUNGLING OGRES is a GREAT ASSET to the neighbohood. It keeps out the RIFF-RAFF." -- Wormy
chris@mimsy.UUCP (Chris Torek) (01/14/88)
>In article <826@murphy.UUCP> dcornutt@murphy.UUCP (Dave Cornutt) writes: >>I have discovered something peculiar about csh variable substitution. Is >>this a bug or am I doing something wrong? [the bug reduces to set x1=test echo ${x1} ] In article <1269@mips.UUCP>, hansen@mips.UUCP (Craig Hansen) writes: >You're doing something wrong. The correct syntax is: >% set xy1z={$xy1z}_123 Naah. *** sh.lex.c.old Wed Jan 13 20:22:06 1988 --- sh.lex.c Wed Jan 13 20:22:10 1988 *************** *** 373,377 **** } } else if (letter(c)) ! while (letter(c = getC(DOEXCL))) { if (np < &name[sizeof name / 2]) *np++ = c; --- 373,377 ---- } } else if (letter(c)) ! while (letter(c = getC(DOEXCL)) || digit(c)) { if (np < &name[sizeof name / 2]) *np++ = c; The amusing part is that the code in sh.dol.c was all set to handle text of the form `{ALPHA}{ALNUM}*', but sh.lex.c never let it get that far. This `Variable syntax' error is coming from the `lexical analyser', not the variable evaluator. That one has one of its own, used if the `lexer' lets something wrong go through. Sheer idiocy: two routines to do the same job. Craig's workaround is fine if the expansion of $xy1z does not contain a comma. % set a=a,b,c % echo ${a} a,b,c % set a1=a,b,c % echo {$a1} a b c Here the {}s indicate set notation, rather than variable name restriction. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris
nortond@mosys.UUCP (Daniel A. Norton) (01/14/88)
I am running a version of csh which comes with Convergent's CTIX
along with Sys V/3.0 and it does the same thing. Put more simply,
if I have a variable name with a digit in it, I cannot expand it
if I enclose the variable name in parentheses:
% set xy1z=asdf
% echo $xy1z
asdf
% echo ${xy1z}
Variable syntax.
I would call this a bug in CTIX, because the documention on csh reads:
$name
${name}
Are replaced by the words of the value of variable
name, each separated by a blank. Braces insulate
name from following characters which would otherwise
be part of it. Shell variables have names consisting of
up to 20 letters and digits starting with a letter. The
underscore character is considered a letter.
--
Daniel A. Norton nortond@mosys.UUCP
544 Cormorant Drive ...uunet!mosys!nortond
Voorhees, NJ 08043 609/751-7381hansen@mips.UUCP (Craig Hansen) (01/15/88)
In article <1530@ogcvax.UUCP>, schaefer@ogcvax.UUCP (Barton E. Schaefer) writes: > In article <mips.1269> hansen@mips.UUCP (Craig Hansen) writes: > >In article <826@murphy.UUCP> dcornutt@murphy.UUCP (Dave Cornutt) writes: > >> I have discovered something peculiar about csh variable substitution. Is > >> this a bug or am I doing something wrong? > > > >You're doing something wrong. The correct syntax is: > > > >% set xy1z={$xy1z}_123 > > Sorry, Craig, that syntax changes the meaning of the {} from "variable > substitution" to "filename substitution" as in > > % set xy1z="one,two,three" > % set xyz={$xy1z}_step > % set > xy1z one,two,three > xyz (one_step two_step three_step) > > The syntax ${xy1z} SHOULD work, but it doesn't (confirmed here for Mt. Xinu > 4.3 BSD csh as well). Does anyone happen to know why it fails? Does it have > anything to do with ${1} being a synonym for $1 (and ${2} for $2 and so on)? OK, OK, it's a bug. I haven't tested the fix, but the following fragment of source file sh.lex.c looks dubious: default: if (digit(c)) { /* * let $?0 pass for now if (special) goto vsyn; */ while (digit(c = getC(DOEXCL))) { if (np < &name[sizeof name / 2]) *np++ = c; } } else if (letter(c)) while (letter(c = getC(DOEXCL))) { if (np < &name[sizeof name / 2]) *np++ = c; } else goto vsyn; Looks like the last call to letter() should be written as: while (letter(c = getC(DOEXCL)) || digit(c)) { There's a macro called alnum(), which would be the obvious replacement, but it evaluates the argument twice :-(. -- Craig Hansen Manager, Architecture Development MIPS Computer Systems, Inc. ...{ames,decwrl,prls}!mips!hansen or hansen@mips.com
steve@edm.UUCP (Stephen Samuel) (01/21/88)
In article <590@devon.UUCP>, paul@devon.UUCP writes: | In article <826@murphy.UUCP> dcornutt@murphy.UUCP (Dave Cornutt) writes: | +---------- | | I have discovered something peculiar about csh variable substitution. Is | | this a bug or am I doing something wrong? Watch this: | | % set xy1z=qwert | | % echo $xy1z | | qwert | | % set xy1z=${xy1z}_123 | | Variable syntax. | | % echo $xy1z | | qwert (bloody include counter.....) It seems to be something with having the '1' inside the braces... The one fix (workaround) I have is to take the qy1z out of the braces and trail it with a null ('') string (delimits the end of the name.): ....... % set qy1z=$qy1z''_123 % echo $qy1z qwert_123 -- ------------- Stephen Samuel Disclaimer: You betcha! {ihnp4,ubc-vision,seismo!mnetor,vax135}!alberta!edm!steve BITNET: USERZXCV@UQV-MTS