#!/usr/bin/tclsh

# Script built on an idea of Jules Bean to extract "what TeX would do" from
# a given macro.
#
# Call it with  texify '\macro' [...] to get a line per item giving ascent,
# descent, width, the font and the position in the font TeX would use to
# typeset the symbol.

# Original script:
#\batchmode
#\def\entails{$1}
#\edef\temp{\entails}
#\message{\string\meaning\temp}
#\setbox5=\box{$\entails$}
#\showbox5
#\bye

set filebase texifytmp
set hboxexp {^\\hbox.([0-9.]+)\+([0-9.]+).x([0-9.]+)}
set fontexp {^\.+\\ten([a-z]+) (.*)$}

foreach item $::argv {
	set font    unknown
	set char    {}
	set value   0
	set ascent  0
	set descent 0
	set width   0

	set f [open $filebase.tex w 0600]
	puts $f "\\nonstopmode"
	puts $f "\\setbox5=\\hbox\{\$$item\$\}"
	puts $f "\\showbox5"
	puts $f ""
	puts $f "\\end"
	close $f

	if {[catch {exec tex $filebase.tex} err]} {
		#puts "Error: '$err'"
	}

	set f [open $filebase.log r]
	while {![eof $f]} {
		gets $f line
		# try to interpret it as a hbox line
		regexp $hboxexp $line dummy ascent descent width
		# try to interpret it as a font line
		regexp $fontexp $line dummy font char
	}
	close $f

	if {![string equal $font "unknown"]} {
		if {[string equal -length 2 $char {^^}]} {
			scan $char "%c%c%c" dummy1 dummy2 value
			set value [expr {$value - 64}]
		} else {
			scan $char "%c" value
		}
	}

	puts [list $ascent $descent $width $font $value $char]
}