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# -*- tcl -*-
# Copyright (c) 2014 Andreas Kupries <andreas_kupries@sourceforge.net>
# Utility commands for parser syntax errors.
# # ## ### ##### ######## ############# #####################
## Requirements
package require Tcl 8.5 ; # Required runtime.
package require char
# # ## ### ##### ######## ############# #####################
##
namespace eval ::pt::util {
namespace export error2readable error2position error2text
namespace ensemble create
namespace import ::char::quote
}
# # ## ### ##### ######## #############
## Public API
proc ::pt::util::error2readable {error text} {
lassign $error _ location msgs
lassign [Position $location $text] l c
lappend map \n \\n
lappend map \r \\r
lappend map \t \\t
# Get 10 chars before and after the failure point. Depending on
# the relative position of input beginning and end we may get less
# back of either. Special characters in the input (line endings,
# tabs) are quoted to keep this on a single line.
set prefix [string map $map [string range $text ${location}-10 $location]]
set suffix [string map $map [string range $text ${location}+1 ${location}+10]]
# Construct a line pointing to the failure position. By using the
# transformed prefix as our source (length) no complex
# calculations are required. It is implicit in the prefix/suffix
# separation above.
set n [string length $prefix]
incr n -1
set point [string repeat - $n]
append point ^
# Print our results.
lappend lines "Parse error at position $location (Line $l, column $c)."
lappend lines "... ${prefix}${suffix} ..."
lappend lines " $point"
lappend lines "Expected one of"
lappend lines "* [join [Readables $msgs] "\n* "]"
lappend lines ""
return [join $lines \n]
}
proc ::pt::util::error2position {error text} {
lassign $error _ location msgs
return [Position $location $text]
}
proc ::pt::util::error2text {error} {
lassign $error _ location msgs
return [Readables $msgs]
}
# # ## ### ##### ######## #############
## Internals
proc ::pt::util::Position {location text} {
incr location -1
# Computing the line/col of a position is quite easy. Split the
# part before the location into lines (at eol), count them, and
# look at the length of the last line in that.
set prefix [string range $text 0 $location]
set lines [split $prefix \n]
set line [llength $lines]
set col [string length [lindex $lines end]]
return [list $line $col]
}
proc ::pt::util::Readables {msgs} {
set cl {}
set r {}
foreach pe $msgs {
switch -exact -- [lindex $pe 0] {
t {
# Fuse to multiple 't'-tags into a single 'cl'-tag.
lappend cl [lindex $pe 1]
}
cl {
# Fuse multiple 'cl'-tags into one.
foreach c [split [lindex $pe 1]] { lappend cl $c }
}
default {
lappend r [Readable $pe]
}
}
}
if {[set n [llength $cl]]} {
if {$n > 1} {
lappend r [Readable [list cl [join [lsort -dict $cl] {}]]]
} else {
lappend r [Readable [list t [lindex $cl 0]]]
}
}
return [lsort -dict $r]
}
proc ::pt::util::Readable {pe} {
set details [lassign $pe tag]
switch -exact -- $tag {
t {
set details [quote string {*}$details]
set m "The character '$details'"
}
n { set m "The symbol $details" }
.. {
set details [quote string {*}$details]
set m "A character in range '[join $details '-']'"
}
str {
set details [join [quote string {*}[split $details {}]] {}]
set m "A string \"$details\""
}
cl {
set details [join [quote string {*}[split $details {}]] {}]
set m "A character in set \{$details\}"
}
alpha { set m "A unicode alphabetical character" }
alnum { set m "A unicode alphanumerical character" }
ascii { set m "An ascii character" }
digit { set m "A unicode digit character" }
graph { set m "A unicode printing character, but not space" }
lower { set m "A unicode lower-case alphabetical character" }
print { set m "A unicode printing character, including space" }
control { set m "A unicode control character" }
punct { set m "A unicode punctuation character" }
space { set m "A unicode space character" }
upper { set m "A unicode upper-case alphabetical character" }
wordchar { set m "A unicode word character (alphanumerics + connectors)" }
xdigit { set m "A hexadecimal digit" }
ddigit { set m "A decimal digit" }
dot { set m "Any character" }
default { set m [string totitle $tag] }
}
return $m
}
# # ## ### ##### ######## ############# #####################
## Ready
package provide pt::util 1.1
return
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