The engine works by converting a template (which is a string, or a file) into a Tcl script, and then running it. Each line of text encountered will be returned as is. Exception is text between <% ... %> which is treated as Tcl code (the eval happens in a regular interp).
expand is a simple and snugly for Tcl language, be mounted in tcllib. You can use it as quick as flash.
But, that library has a problem, when to really use. We cannot write easily following signs
[ ] { }
DDG No! We can easily write
[ ] { }
with expand if we use alternative brackets for expansion:
(Tclkit) 24 % package require textutil::expander 1.3.1 (Tclkit) 25 % textutil::expander exp ::exp (Tclkit) 26 % set string {[] {} <% set x %> } [] {} <% set x %> (Tclkit) 27 % set x 65 65 (Tclkit) 28 % exp expand $string {<% %>} [] {} 65
TemplaTcl is a powerful and cool template engine.
But now, we cannot use it on Tcl8.4 :(
a simple and fast template engine. That still not have function to read a file, create a parser object.
But we can use it instant, only write a command require or source.
Simple variable substitution is done with "<%= $variable %>" (e.g., Thanks <%=$count%> accesses!).
Simple expression substitution is done with "<%:Tcl expression%>" (e.g., <%:$i+2000%>).
First, let's create a template file (templtest.tmpl):
<table><% for {set i 0} {$i < 4} {incr i} { %> <tr> <td><%= $i %></td> </tr><% } %> </table> <ul> <% foreach item $cityList { %><li><%= $item %> <% } %> </ul>
The above template (in HTML language) generates a 4-row table and an unordered list, taking values from a $cityList variable that we're going to define. First let's load the code:
source tmpl_parser.tcl
reading template file.
set fd [open templtest.tmpl r] set tmpl [read $fd] close $fd
now create a parser instance:
set parser [::tmpl_parser::tmpl_parser $tmpl]
set the variables used in our template:
set cityList {Ragusa Ravenna Rieti Rimini Rome Rovigo}
and render the template:
puts [eval $parser]
Here's the output that gets produced:
<table> <tr> <td>1</td> </tr> <tr> <td>2</td> </tr> <tr> <td>3</td> </tr> <tr> <td>4</td> </tr> </table> <ul> <li>Ragusa <li>Ravenna <li>Rieti <li>Rimini <li>Rome <li>Rovigo </ul>
# tmpl_parser.tcl # # Tcl embeddedd script parser(a template engine) # # This module comverts Tcl embedded scripts into a Tcl normal script(parser), # after you just have to do eval command for the generated parser. # # Copyright (c) 2007 by Kanryu KATO<[email protected]> # licensed on Tcl License. package require Tcl 8.3 package provide tmpl_parser 0.1 namespace eval ::tmpl_parser { namespace export tmpl_parser } proc ::tmpl_parser::tmpl_parser {tmpl} { # Tcl embedded tags # [[outer <%...inner...%> outer]] <-$tmpl # [ = ] <-$token # cd ef hi j <-indexes set parser { {set _o {}} } while {[set i [string first %> $tmpl]] != -1} { set h [expr {$i-1}] set j [expr {$i+2}] set token [string range $tmpl 0 $h] set d [string first <% $token] set c [expr {$d-1}] set e [expr {$d+2}] set f [expr {$d+3}] # outer lappend parser [escaped_parse [string range $token 0 $c]] switch [string index $token $e] { "=" { # normal expression (e.g., Thanks <%=$count%> accesses!) lappend parser [normal_parse [string range $token $f end]] } ":" { # numeric expression (e.g., <%:$i+2000%>) lappend parser [numeric_parse [string range $token $f end]] } default { # embedded Tcl command is passed through listing lappend parser [string range $token $e end] } } # after "%>" set tmpl [string range $tmpl $j end] } #last outer lappend parser [escaped_parse $tmpl] lappend parser {join $_o ""} return [join $parser "\n"] } proc ::tmpl_parser::escaped_parse {str} { set str [string map {\" \\\" \{ \\\{ \} \\\} \\ \\\\} $str] return "lappend _o \"$str\"" } proc ::tmpl_parser::normal_parse {str} { return "lappend _o $str" } proc ::tmpl_parser::numeric_parse {str} { return "lappend _o [expr $str]" }