[Richard Suchenwirth] 2000-11-21 - Here's a tiny script (executable for Unix) that takes 1..3 Tcl scripts (not files - literal code!) as arguments and evaluates
   * the first (if more than one - may be an empty string) in the beginning
   * the second (or first if only one) for each line from stdin
   * the third (if present) in the end: after eof on stdin
This is of course modeled after the 'BEGIN{this}{that}END{finally}' pattern of awk scripts, 
but I didn't want to introduce special keywords. To make it more awk-like, I however introduced special variables FS (field separator), OFS (output field separator), NF (number of fields in current line), 
NR (number of records - lines - so far), 0 (the whole input line), 1..$NF (fields as split by FS; 
you get the last field with [[set $NF]]).

I use this script for short Tcl tasks that I don't want to write a program file for, e.g.
  owh '' 'lappend t $0' 'puts [join [lsort -index end -integer -decreasing $t] \n]'
to sort output of a pipe the way I want it, but it can be used simply like
 owh 'puts [string toupper $0]'
 owh 'set n 0' 'incr n' 'puts $n' <infile ;# substitutes 'wc -l'
 owh '' '' 'set NR' <infile               ;# ditto, just more compact
 owh 'if $NR>10 break; puts $0' <infile   ;# substitutes 'head'
As for awk, the scripts should be single-quoted so the shell doesn't see all those dollars, brackets etc. These single quotes are not seen by tclsh.
 #!/usr/bin/env tclsh

 if {[llength $argv]<1} {
        puts "usage: owh ?init? body ?exit?
        performs body (in Tcl) for each line (\$0) from stdin
        owh: Ousterhout - Welch - Hobbs, to name a few"
        exit -1
 }
 proc awksplit {text {split default}} {
    set no 0
    if {$split!="default"} {
        set t [split $text $split]
    } else {
        eval set t [list $text]
    }
    uplevel 1 [list set NF [llength $t]]
    foreach i $t {uplevel 1 [list set [incr no] $i]}
    uplevel 1 {set 0 "";trace variable 0 ru 0}
 }
 proc 0 {_name index op} {
    switch $op {
        r {
            uplevel {
                set 0 ""
                for {set i 1} {$i<=$NF} {incr i} {lappend 0 [set $i]}
                set 0 [join $0 $OFS]
            }
        }
        u {rename 0 {} ;# leave no traces of the trace..}
    }
 } 
 proc print s {if [catch {puts $s}] exit} ;# good for broken pipe

 set FS default
 set OFS " "

 if {[llength $argv]>1} {
    eval [lindex $argv 0]
    set _body [lindex $argv 1] ;# strip outer braces
    set _exit [lindex $argv 2]
 } else {
    set _body [lindex $argv 0] ;# strip outer braces
    set _exit {}
 }

 set NR 1
 while 1 {
    gets stdin line
    if [eof stdin] break
    awksplit $line $FS
    eval $_body
    incr NR
 }
 set res [eval $_exit]
 if [string length $res] {puts $res}
----

Okay Richard, just to prove that I really am on it, here's
the current state of perlytcl (gimme a coupla days to finish!):

 #!/bin/sh
 # use -*-Tcl-*- \
 exec tclsh "$0" "$@"
 set awk   0
 set print 1
 set bak   {}
 foreach arg $args {
   # if we are doing in-place edits, get the bak pattern
   regexp {^(-[an]*i)\.?(.+)?} $arg -> arg bak 
   switch -exact -- $arg {
     -an -
     -na -
      -a -
      -n { # default will be to print, so we won't support p
            if { [ regexp {a} $arg ] } {
               set awk 1
            }
            if { [ regexp {n} $arg ] } {
               set print 0
            }
         }
    -ani -
    -nai -
      -i {
         }
    -ane -
    -nae -
      -e { # script follows! then filenames
         }
 default {
            if { [ string match $switch -e ] } {
               set cmd $arg
               set switch {}   
            # sorry, we silently lose non-existent files
            } elseif { [ file exists $arg ] } {
               lappend files $arg
            }   
         }
   } # end of switch   
 }

 foreach file $files {
 }

----
 <Csan>
 A little patch which adds
 
  llindex list index ?index? ...
 
 Here it is:
 
 # diff -Naur ./owh.tcl~ ./owh.tcl
 --- ./owh.tcl~ Fri Oct 19 15:11:46 2001
 +++ ./owh.tcl  Fri Oct 19 15:40:00 2001
 @@ -31,6 +31,12 @@
          u {rename 0 {} ;# leave no traces of the trace..}
      }
   }
 + proc llindex {list args} {
 +   foreach index $args {
 +     append indices [lindex $list $index]
 +   }
 +   return $indices
 + }
  
   set FS default
   set OFS " "

----
So, what is the benefit of the llindex addition here?

----
Here's a simple ''zsh'' macro that allows a quick call to Tcl with a single command:
 suchenwi@jaguar% tcl () { echo "puts [eval $*]" | tclsh } 
 suchenwi@jaguar% tcl expr 17/4.
 4.25
 suchenwi@jaguar% tcl "puts [llength {1 2 3}]; set _ hello"
 3
 hello
 suchenwi@jaguar%
----
I get similar functionality in ksh when I type:
 $ tcl()
 {
 echo "puts [eval $*]" | tclsh
 } 
----
This can actually be accomplished in Windoze too with help of the DosKey command.
Put the following line in a text file:
 tcl=echo puts [eval $*] | tclsh
Activate the command with
 doskey/macrofile=<filename>
Then run (it will of course only work interactively as all DosKey commands, 
but I guess that was what we wanted too. :)
 C:\> tcl expr 17/4.
 4.25
 C:\> tcl puts [llength {1 2 3}]; set _ hello
 3
 hello

----

In bash you can do:
 function tcl () { echo "puts [eval $*]" | tclsh; };


----
[AM] (20 february 2009) Reading [David Welton]'s comparison between Tcl and Ruby 
[http://journal.dedasys.com/2006/03/06/ruby-vs-tcl], I was reminded of this page.
And I thought I'd have another go at a command-line utility. It is not at all
polished, just a proof of concept. As it sometimes faster to write your own 
stuff than adapt existing code, I did so - with the intention of using the 
code in this page for improving the program below:

======
# owhnew.tcl --
#     First experimental implementation of a command line utility
#     Note:
#     Use the OWH Wiki page for more AWK-like functionality
#

# analyseCommandLine --
#     Analyse the command line
#
# Arguments:
#     argv            List of command-line arguments
#
# Result:
#     List of files to handle
#
# Side effects:
#     Sets various global variables
#
proc analyseCommandLine {argv} {

    set ::mode   e
    set ::parse  0
    set ::regexp ""

    foreach arg $argv {
        switch -glob -- $arg {
            "--" {
                 set argv [lrange $argv 1 end]
                 break
            }
            "-e*" {
                 set ::mode e
                 set ::cmd  [lindex $argv 1]
                 if { [string first {$0} $::cmd] < 0 } {
                     set ::cmd "$::cmd \$0"
                 }
                 if { [string match {$[0-9]} $::cmd] } {
                     set parse 1
                 }
                 set argv   [lrange $argv 1 end]
            }
            "-p*" {
                 set ::mode p
                 set ::cmd  [lindex $argv 1]
                 if { [string first {$0} $::cmd] < 0 } {
                     set ::cmd "$::cmd \$0"
                 }
                 if { [string match {$[0-9]} $::cmd] } {
                     set parse 1
                 }
                 set argv   [lrange $argv 1 end]
            }
            "-r*" {
                 set ::mode   r
                 set ::regexp [lindex $argv 1]
                 set argv     [lrange $argv 1 end]
            }
            "-h" {
                 printHelp
            }
            default {
                 break
            }
        }
        #
        # Remove this argument
        #
        set argv [lrange $argv 1 end]
    }

    return $argv
}

# parseLine --
#     Parse the line that was read
#
# Arguments:
#     line            Line to be parsed
#
# Result:
#     None
#
# Side effects:
#     Sets global variables 1, 2, 3, ...
#
proc parseLine {line} {

    set line [string map {\{ \\\{ \} \\\} \" \\\" \; \\\;} $line]

    set n 0
    foreach field [split $line] {
        incr n
        set ::$n $field
    }
}

# printHelp --
#     Print information on the use
#
# Arguments:
#     None
#
# Result:
#     None
#
proc printHelp {} {
    puts \
"Usage: [file tail $::script] -\[eprh] command file1 file2 ...
Examples:

To print the file in lower-case:
   [file tail $::script] -e 'string tolower' file.inp

To print the first word of each line:
   [file tail $::script] -e '\$1' file.inp

To print those lines that aer longer than 20 characters:
   [file tail $::script] -p '[string length \$0] > 20' file.inp

To find all lines containing \"list\" (or any regular expression):
   [file tail $::script] -r 'list' file.inp

Note: \$1, \$2, \$3, ... are the words on the line, \$0 is the complete line

Note on regular expressions:
Not all RE syntax works for mysterious reasons - backslashes fail for instance
"
}

# main --
#     Analyse the command-line arguments and act upon the result
#

set script [info script]
set argv [analyseCommandLine $argv]

foreach f $argv {
    set infile [open $f r]

    switch -- $mode {
        "e" {
            if { ! $parse } {
                while { [gets $infile 0] >= 0 } {
                    puts [eval $cmd]
                }
            } else {
                while { [gets $infile 0] >= 0 } {
                    parseLine $0
                    puts [eval $cmd]
                }
            }
        }
        "p" {
            if { ! $parse } {
                while { [gets $infile 0] >= 0 } {
                    if $cmd {
                        puts $0
                    }
                }
            } else {
                while { [gets $infile 0] >= 0 } {
                    parseLine $0
                    if $cmd {
                        puts $0
                    }
                }
            }
        }
        "r" {
            while { [gets $infile 0] >= 0 } {
                if { [regexp $regexp $0] } {
                    puts $0
                }
            }
        }
    }
    close $infile
} 

======
----
[Category Application] - [Category String Processing]