== Extending tcl to generate html ==
CMcC Following from jenglish's comment: why learn to use a monster HTML-template library when you can, with a few lines of code, extend the base language so you can write things like [<A> href "/home.html" { ! "Home" }] ... I wrote the following to do just that using the techniques in let unknown know.
package require know
know {[string match <*> [lindex $args 0]]} {
set tag [string trim [lindex $args 0] "<>"]
::proc ::<$tag> {args} [string map [list @T $tag] {
set result {}
foreach {n v} [lrange $args 0 end-1] {
lappend result "$n='[armour $v]'"
}
return "<@T [join ${result}]>[lindex $args end]</@T>"
}]
return [eval $args]
}This will generate a proc for any command like [<li>] which will do pretty much what you'd expect it to.
== Armouring HTML ==
Prevent output from containing html-significant characters
interp alias {} armour {} string map {& & < < > > \" " ' '} ... fairly clearly ''that'' needs some work :)== Functional HTML generation ==
Often what you want isn't to iterate, but to convert a list into something else. One generic technique I've found helpful is the use of join, as follows:
<ul><li>[[join $list </li></li>]</li></ul>
Which will convert a tcl list into an HTML unordered list. Similar techniques are possible with <table>s
The technique can be readily made generic:
== Subst-if ==
Here's a variant of if which evaluates its conditional using subst and not eval
proc If {args} {
while {[llength $args] && ![uplevel expr [lindex $args 0]]} {
set args [lrange $args 2 end] ;# lose the cond and positive-cond
if {[lindex $args 0] eq "elseif"} {
set args [lrange $args 1 end]
continue ;# continue to evaluate conditionals
} elseif {[lindex $args 0] eq "else"} {
break
}
}
return [uplevel subst [list [lindex $args 1]]] ;# return with neg-consequence
}
set a 1; set b 2
puts [If {$a} {a is true} else {a is false}]
puts [If {$a == $b} {a == b} elseif {$b == 1} {b is 1} else {b is not 1 it is $b}]