source(3tcl) [debian man page]

source(3tcl)						       Tcl Built-In Commands						      source(3tcl)

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NAME

       source - Evaluate a file or resource as a Tcl script

SYNOPSIS

       source fileName

       source -encoding encodingName fileName													   |
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DESCRIPTION

       This  command takes the contents of the specified file or resource and passes it to the Tcl interpreter as a text script.  The return value
       from source is the return value of the last command executed in the script.  If an error occurs in evaluating the contents  of  the  script
       then  the source command will return that error.  If a return command is invoked from within the script then the remainder of the file will
       be skipped and the source command will return normally with the result from the return command.

       The end-of-file character for files is "32" (^Z) for all platforms.  The source command will  read  files  up  to  this  character.   This
       restriction  does  not  exist for the read or gets commands, allowing for files containing code and data segments (scripted documents).	If
       you require a "^Z" in code for string comparison, you can use "32" or "u001a", which will be safely substituted by the  Tcl  interpreter
       into "^Z".

       The  -encoding  option  is  used  to specify the encoding of the data stored in fileName.  When the -encoding option is omitted, the system |
       encoding is assumed.

EXAMPLE

       Run the script in the file foo.tcl and then the script in the file bar.tcl:
	      source foo.tcl
	      source bar.tcl
       Alternatively:
	      foreach scriptFile {foo.tcl bar.tcl} {
		 source $scriptFile
	      }

SEE ALSO

       file(3tcl), cd(3tcl), encoding(3tcl), info(3tcl)

KEYWORDS

       file, script

Tcl																      source(3tcl)

eval(3tcl)						       Tcl Built-In Commands							eval(3tcl)

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NAME

       eval - Evaluate a Tcl script

SYNOPSIS

       eval arg ?arg ...?
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DESCRIPTION

       Eval  takes  one  or more arguments, which together comprise a Tcl script containing one or more commands.  Eval concatenates all its argu-
       ments in the same fashion as the concat command, passes the concatenated string to the Tcl interpreter recursively, and returns the  result
       of  that  evaluation  (or any error generated by it).  Note that the list command quotes sequences of words in such a way that they are not
       further expanded by the eval command.

EXAMPLES

       Often, it is useful to store a fragment of a script in a variable and execute it later on with extra values  appended.  This  technique	is
       used  in  a  number of places throughout the Tcl core (e.g. in fcopy, lsort and trace command callbacks). This example shows how to do this
       using core Tcl commands:
	      set script {
		  puts "logging now"
		  lappend $myCurrentLogVar
	      }
	      set myCurrentLogVar log1
	      # Set up a switch of logging variable part way through!
	      after 20000 set myCurrentLogVar log2

	      for {set i 0} {$i<10} {incr i} {
		  # Introduce a random delay
		  after [expr {int(5000 * rand())}]
		  update    ;# Check for the asynch log switch
		  eval $script $i [clock clicks]
	      }

       Note that in the most common case (where the script fragment is actually just a list of words forming a command prefix), it  is	better	to |
       use  {*}$script	when  doing this sort of invocation pattern.  It is less general than the eval command, and hence easier to make robust in |
       practice.  The following procedure acts in a way that is analogous to the lappend command, except it inserts the  argument  values  at  the
       start of the list in the variable:
	      proc lprepend {varName args} {
		 upvar 1 $varName var
		 # Ensure that the variable exists and contains a list
		 lappend var
		 # Now we insert all the arguments in one go
		 set var [eval [list linsert $var 0] $args]
	      }
       However, the last line would now normally be written without eval, like this:								   |
	      set var [linsert $var 0 {*}$args] 												   |

SEE ALSO

       catch(3tcl), concat(3tcl), error(3tcl), interp(3tcl), list(3tcl), namespace(3tcl), subst(3tcl), tclvars(3tcl), uplevel(3tcl)

KEYWORDS

       concatenate, evaluate, script

Tcl																	eval(3tcl)