Edit:
I was trying to replace "xor_in0" with "xor_in[0]" and "xor_in1" with "xor_in[1]" for a given str parameter. Here "xor_in0", "xor_in1" is parameter passed in and I represent it as "key", and "xor_in[0]", "xor_in[1]" is the value parameter stored in an array. Notice the point here is to replace every "key" in "str" with "value" . Here is my testing code:
set str "(xor_in0^xor_in1)"
set str1 "xor_in0^xor_in1" # another input
set key "xor_in0"
set value "xor_in\[0\]"
set newstr ""
set nonalpha "\[^0-9a-zA-Z\]"
regsub -all [subst {^\[(*\]($key)($nonalpha+)}] $str [subst -nobackslashes {$value\2}] newstr
puts $newstr
But somehow it doesn't work... I also tried to remove [subst ...] and it still failed to match anything. This is somehow against my knowledge of regular expression. Please help.
Everything seems a bit over-complicated to me.
Let's look at the regsub that you're actually going to execute. There's a trick to doing that easily; if your command is:
regsub -all [subst {^\[(*\]($key)($nonalpha+)}] $str [subst -nobackslashes {$value\2}] newstr
Then we can print out what it's going to try to do with:
puts [list regsub -all [subst {^\[(*\]($key)($nonalpha+)}] $str [subst -nobackslashes {$value\2}] newstr]
That reveals that you're really doing this:
regsub -all {^[(*](xor_in0)([^0-9a-zA-z]+)} (xor_in0^xor_in1) {xor_in[0]\2} newstr
The part that looks a bit strange in there is the ([^0-9a-zA-z]+) at the end of the RE. It's legal but odd as we can write things a bit differently with \W for matching a non-alpha:
regsub -all {^[(*](xor_in0)(\W+)} $str {xor_in[0]\2} newstr
And that seems to work. What might the bug be then? The definition of nonalpha, as you're using "\[^0-9a-zA-z\]" instead of "\[^0-9a-zA-Z\]". Yes, a literal ^ lies in the ASCII (and Unicode) range from A to z…
OTOH, I'd actually expect a transformation to really be done like this:
set newstr [regsub -all {(\y[a-zA-Z]+_in)(\d+)} $str {\1[\2]}]
The only things you're not used to there are \y (a word boundary constraint) and \d (match any digit). Or, for a simple transformation (mapping all instances of a literal substring to another literal substring):
set newstr [string map [list $key $value] $str]
Actually the real problem to my question is the A-z typo :)
Simple is generally better:
regsub -all {\d+} $s {[&]} s
Takes care of your examples.
Related
I'm trying to edit a verilog file by finding a match in lines of a file and replacing the match by "1'b1". The problem is that the match is a bus with square brackets in the form "busname[0-9]".
for example in this line:
XOR2X1 \S12/gen_fa[8].fa_i/x0/U1 ( .A(\S12/bcomp [8]), .B(abs_gx[8]), .Y(
I need to replace "abs_gx[8]" by "1'b1".
So I tried to find a match by using this code:
#gets abs_gx[8]
set net "\{[lindex $data 0]\}"
#gets 1'b1
set X [lindex $data 1]
#open and read lines of file
set netlist [open "./$circuit\.v" r]
fconfigure $netlist -buffering line
gets $netlist line
#let's assume the line is XOR2X1 \S12/gen_fa[8].fa_i/x0/U1 ( .A(\S12/bcomp [8]), .B(abs_gx[8]), .Y(
if {[regexp "(.*.\[A-X\]\()$net\(\).*)" $line -inline]} {
puts $new "$1 1'b$X $2" }
elseif {[regexp "(.*.\[Y-Z\]\()$net(\).*)" $line]} {
puts $new "$1$2" }
else {puts $new $line}
gets $netlist line
I tried so much things and nothing seems to really match or I get an error because 8 is not a command because [8] gets interpreted as a command.
Any sneaky trick to place a variable in a regex without having it interpreted as a regular expression itself?
If you have an arbitrary string that you want to match exactly as part of a larger regular expression, you should precede all non-alphanumeric characters in the string by a backslash (\). Fortunately, _ is also not special in Tcl's REs, so you can use \W (equivalent to [^\w]) to match the characters you need to fix
set reSafe [regsub -all {\W} $value {\\&}]
If you're going to be doing that a lot, make a helper procedure.
proc reSafe {value} {
regsub -all {\W} $value {\\&}
}
(Yes, I'd like a way of substituting variables more directly, but the RE engine's internals are code I don't want to touch…)
If I understand correctly, you want to substitute $X for $net except when $net is preceded by Y( or Z( in which case you just delete $net. You could avoid the complications of regexp by using string map which just does literal substitutions - see https://www.tcl-lang.org/man/tcl8.6/TclCmd/string.htm#M34 . You would then need to specify the Y( and Z( cases separately, but that's easy enough when there are only two. So instead of the regsub lines you would do:
set line [string map [list Y($net Y( Z($net Z( $net $X] $line]
puts $new $line
I want to go through a comma separated string and replace matches with more comma separated elements.
i.e 5-A,B after the regsub should give me 1-A,2-A,3-A,4-A,5-A,B
The following is not working for me as & is being passed as an actual & instead of the actual match:
regsub -all {\d+\-\w+} $string [myConvertProc &]
However not attempting to pass the & and using it directly works:
regsub -all o "Hello World" &&&
> Hellooo Wooorld
Not sure what I am doing wrong in attempting to pass the value & holds to myConvertProc
Edit: I think my initial problem is the [myConvertProc &] is getting evaluated first, so I am actually passing '&' to the procedure.
How do I get around this within the regex realm? Is it possible?
Edit 2: I've already solved it using a foreach on a split list, so I'm just looking to see if this is possible within a regsub. Thanks!
You are correct in your first edit: the problem is that each argument to regsub is fully evaluated before executing the command.
One solution is to insert a command substitution string into the string, and then use subst on it:
set string [regsub -all {\d+\-\w+} $string {[myConvertProc &]}]
# -> [myConvertProc 5-A],B
set string [subst $string]
# -> 1-A,2-A,3-A,4-A,5-A,B
This will only work if there is nothing else in string that is subject to substitution (but you can of course turn off variable and backslash substitution).
The foreach solution is much better. An alternative foreach solution is to iterate over the result of regexp -indices -inline -all, but iterating over the parts of a split list is preferable if it works.
Update:
A typical foreach solution goes like this:
set res {}
foreach elem [split $string ,] {
if {[regexp -- {^\d+-\w+$} $elem]} {
lappend res [myConvertProc $elem]
} else {
lappend res $elem
}
}
join $res ,
That is, you collect a result list by looking at each element in the raw list. If the element matches your requirement, you convert it and add the result to the result list. If the element doesn't match, you just add it to the result list.
It can be simplified somewhat in Tcl 8.6:
join [lmap elem [split $string ,] {
if {[regexp -- {^\d+-\w+$} $elem]} {
myConvertProc $elem
} else {
set elem
}
}] ,
Which is the same thing, but the lmap command handles the result list for you.
Documentation: foreach, lappend, lmap, regexp, regsub, set, split, subst
TCL/TK:
Problem: I want to be able to get the post-match string data, but even though I provide
regexp with more than a variable for the match itself the secutive variables either turn out empty, or I got the same value from the first two.
E.g:
set args "!do dance"
regsub -all {(!do)} $args prefix command
puts $prefis "!do"
puts $command "!do"
What to do? Ty
EDIT I found the solution thanks to inspiration by your answer, here's a snippet
if { [ regsub {(!do\s+)} $args "" match ] >= 1 } {
if { $match == "{help}" }
Assuming you want to remove the "!do" then you can do the following:
set args "!do dance"
regsub -all {(!do)} $args "" output
puts $output
I'm not sure why you're using regexp here, and it seems like you're using eggdrop or something. You can easily use:
set prefix [lindex $args 0]
set command [lindex $args 1]
Though you should be careful with $args. It's usually used in procs to mean all the other arguments passed on to the proc aside from the already defined arguments.
% puts $prefix
!do
% puts $command
dance
If i have a string such as:
foo_image_v001.ext
that could just as easily say
bar_image_v001.ext
How can i use TCL to strip the first underscore and everything to the right of it, leaving me with just 'foo' or 'bar'
Im normally a python guy, not very versed in TCL, but it will work best in this case if i can just get it to work =)
Replace everything after the first _
set new [regsub {_.*} $old {}]
Here is one way to do it:
set filename foo_image_v001.ext
set prefix [regsub {_.*} $filename ""]
the regsub looks for the pattern {_.*} in $filename, and replace it with nothing "".
Maybe you could use this?
set string "foo_image_v001.ext"
regexp -- {^([^_]+)} $string - var
foo gets stored in $var.
Don't need to break out a regular expression for this:
using string commands:
set prefix [string range $filename 0 [expr {[string first _ $filename] - 1}]]
Also, if you split the string on underscores, what you want is the first element in the resulting list:
set prefix [lindex [split $filename _] 0]
I have been wondering about a regexp matching pattern in Tcl for some time and I've remained stumped as to how it was working. I'm using Wish and Tcl/Tk 8.5 by the way.
I have a random string MmmasidhmMm stored in $line and the code I have is:
while {[regexp -all {[Mm]} $line match]} {
puts $data $match
regsub {[Mm]} $line "" line
}
$data is a text file.
This is what I got:
m
m
m
m
m
m
While I was expecting:
M
m
m
m
M
m
I was trying some things to see how changing a bit would affect the results when I got this:
while {[regexp -all {^[Mm]} $line match]} {
puts $data $match
regsub {[Mm]} $line "" line
}
I get:
M
m
m
Surprisingly, $match keeps the case.
I was wondering why in the first case, $match automatically becomes lowercase for some reason. Unless I am not understanding how the regexp actually is working, I'm not sure what I could be doing wrong. Maybe there's a flag that fixes it that I don't know about?
I'm not sure I'll really use this kind of code some day, but I guess learning how it works might help me in other ways. I hope I didn't miss anything in there. Let me know if you need more information!
The key here is in your -all flag. The documentation for that said:
-all -- Causes the regular expression to be matched as many times as possible in the string, returning the total number of matches found. If this is specified with match variables, they will contain information for the last match only.
That means the variable match contains the very last match, which is a lower case 'm'. Drop the -all flag and you will get what you want.
Update
If your goal is to remove all 'm' regardless of case, that whole block of code can be condensed into just one line:
regsub -all {[MM]} $line "" line
Or, more intuitively:
set line [string map -nocase {m ""} $line]; # Map all M's into nothing