diff options
| -rw-r--r-- | ChangeLog | 8 | ||||
| -rw-r--r-- | library/init.tcl | 233 |
2 files changed, 222 insertions, 19 deletions
@@ -1,3 +1,11 @@ +2008-12-16 Donal K. Fellows <dkf@users.sf.net> + + TIP #329 IMPLEMENTATION + + * library/init.tcl (throw, try): Implementation of commands documented + in TIP. This implementation is in Tcl and is a stop-gap until + higher-performance ones can be written. + 2008-12-16 Don Porter <dgp@users.sourceforge.net> * generic/tcl.h: Add TIP 338 routines to stub table. diff --git a/library/init.tcl b/library/init.tcl index 084ddbc..dfb1777 100644 --- a/library/init.tcl +++ b/library/init.tcl @@ -3,7 +3,7 @@ # Default system startup file for Tcl-based applications. Defines # "unknown" procedure and auto-load facilities. # -# RCS: @(#) $Id: init.tcl,v 1.115 2008/10/16 17:04:58 dgp Exp $ +# RCS: @(#) $Id: init.tcl,v 1.116 2008/12/16 16:36:08 dkf Exp $ # # Copyright (c) 1991-1993 The Regents of the University of California. # Copyright (c) 1994-1996 Sun Microsystems, Inc. @@ -113,6 +113,201 @@ namespace eval tcl { } } +# TIP #329: [try] and [throw] +# These are *temporary* implementations, to be replaced with ones in C and +# bytecode at a later date before 8.6.0 +namespace eval ::tcl::control { + # These are not local, since this allows us to [uplevel] a [catch] rather + # than [catch] the [uplevel]ing of something, resulting in a cleaner + # -errorinfo: + variable em {} + variable opts {} + + variable magicCodes { ok 0 error 1 return 2 break 3 continue 4 } + + namespace export throw try + + # ::tcl::control::throw -- + # + # Creates an error with machine-readable "code" parts and + # human-readable "message" parts. + # + # Arguments: + # throw - list describing errorcode + # message - Human-readable version of error + proc throw {type message} { + return -code error -errorcode $type -errorinfo $message -level 1 \ + $message + } + + # ::tcl::control::try -- + # + # Advanced error handling construct. + # + # Arguments: + # See try(n) for details + proc try {args} { + variable magicCodes + + # ----- Parse arguments ----- + + set trybody [lindex $args 0] + set finallybody {} + set handlers [list] + set i 1 + + while {$i < [llength $args]} { + switch -- [lindex $args $i] { + "on" { + incr i + set code [lindex $args $i] + if {[dict exists $magicCodes $code]} { + set code [dict get $magicCodes $code] + } elseif {![string is integer -strict $code]} { + set msgPart [join [dict keys $magicCodes] {", "}] + error "bad code '[lindex $args $i]': must be\ + integer or \"$msgPart\"" + } + lappend handlers [lrange $args $i $i] \ + [format %d $code] {} {*}[lrange $args $i+1 $i+2] + incr i 3 + } + "trap" { + incr i + if {![string is list [lindex $args $i]]} { + error "bad prefix '[lindex $args $i]':\ + must be a list" + } + lappend handlers [lrange $args $i $i] 1 \ + {*}[lrange $args $i+1 $i+2] + incr i 3 + } + "finally" { + incr i + set finallybody [lindex $args $i] + incr i + break + } + default { + error "bad handler '[lindex $args $i]': must be\ + \"on code varlist body\", or\ + \"trap prefix varlist body\"" + } + } + } + + if {($i != [llength $args]) || ([lindex $handlers end] eq "-")} { + error "wrong # args: should be\ + \"try body ?handler ...? ?finally body?\"" + } + + # ----- Execute 'try' body ----- + + variable em + variable opts + set EMVAR [namespace which -variable em] + set OPTVAR [namespace which -variable opts] + set code [uplevel 1 [list ::catch $trybody $EMVAR $OPTVAR]] + + if {$code == 1} { + set line [dict get $opts -errorline] + dict append opts -errorinfo \ + "\n (\"[lindex [info level 0] 0]\" body line $line)" + } + + # Keep track of the original error message & options + set _em $em + set _opts $opts + + # ----- Find and execute handler ----- + + set errorcode {} + if {[dict exists $opts -errorcode]} { + set errorcode [dict get $opts -errorcode] + } + set found false + foreach {descrip oncode pattern varlist body} $handlers { + if {!$found} { + if { + ($code != $oncode) || ([lrange $pattern 0 end] ne + [lrange $errorcode 0 [llength $pattern]-1] ) + } then { + continue + } + } + set found true + if {$body eq "-"} { + continue + } + + # Handler found ... + + # Assign trybody results into variables + lassign $varlist resultsVarName optionsVarName + if {[llength $varlist] >= 1} { + upvar 1 $resultsVarName resultsvar + set resultsvar $em + } + if {[llength $varlist] >= 2} { + upvar 1 $optionsVarName optsvar + set optsvar $opts + } + + # Execute the handler + set code [uplevel 1 [list ::catch $body $EMVAR $OPTVAR]] + + if {$code == 1} { + set line [dict get $opts -errorline] + dict append opts -errorinfo \ + "\n (\"[lindex [info level 0] 0] ... $descrip\"\ + body line $line)" + # On error chain to original outcome + dict set opts -during $_opts + } + + # Handler result replaces the original result (whether success or + # failure); capture context of original exception for reference. + set _em $em + set _opts $opts + + # Handler has been executed - stop looking for more + break + } + + # No catch handler found -- error falls through to caller + # OR catch handler executed -- result falls through to caller + + # ----- If we have a finally block then execute it ----- + + if {$finallybody ne {}} { + set code [uplevel 1 [list ::catch $finallybody $EMVAR $OPTVAR]] + + # Finally result takes precedence except on success + + if {$code == 1} { + set line [dict get $opts -errorline] + dict append opts -errorinfo \ + "\n (\"[lindex [info level 0] 0] ... finally\"\ + body line $line)" + # On error chain to original outcome + dict set opts -during $_opts + } + if {$code != 0} { + set _em $em + set _opts $opts + } + + # Otherwise our result is not affected + } + + # Propagate the error or the result of the executed catch body to the + # caller. + dict incr _opts -level + return -options $_opts $_em + } +} +namespace import ::tcl::control::* + # Windows specific end of initialization if {(![interp issafe]) && ($tcl_platform(platform) eq "windows")} { @@ -179,9 +374,9 @@ if {[interp issafe]} { -subcommands { add clicks format microseconds milliseconds scan seconds }] - + # Auto-loading stubs for 'clock.tcl' - + foreach cmd {add format scan} { proc ::tcl::clock::$cmd args { variable TclLibDir @@ -276,7 +471,7 @@ proc unknown args { if {$code == 1} { # # Compute stack trace contribution from the [uplevel]. - # Note the dependence on how Tcl_AddErrorInfo, etc. + # Note the dependence on how Tcl_AddErrorInfo, etc. # construct the stack trace. # set errorInfo [dict get $opts -errorinfo] @@ -407,7 +602,7 @@ proc unknown args { # library file to create the procedure. Returns 1 if it successfully # loaded the procedure, 0 otherwise. # -# Arguments: +# Arguments: # cmd - Name of the command to find and load. # namespace (optional) The namespace where the command is being used - must be # a canonical namespace as returned [namespace current] @@ -431,7 +626,7 @@ proc auto_load {cmd {namespace {}}} { # info commands $name # Unfortunately, if the name has glob-magic chars in it like * # or [], it may not match. For our purposes here, a better - # route is to use + # route is to use # namespace which -command $name if {[namespace which -command $name] ne ""} { return 1 @@ -462,7 +657,7 @@ proc auto_load {cmd {namespace {}}} { # of available commands. Returns 1 if the index is loaded, and 0 if # the index is already loaded and up to date. # -# Arguments: +# Arguments: # None. proc auto_load_index {} { @@ -552,7 +747,7 @@ proc auto_qualify {cmd namespace} { return [list [string range $cmd 2 end]] } } - + # Potentially returning 2 elements to try : # (if the current namespace is not the global one) @@ -610,13 +805,13 @@ proc auto_import {pattern} { # auto_execok -- # -# Returns string that indicates name of program to execute if +# Returns string that indicates name of program to execute if # name corresponds to a shell builtin or an executable in the -# Windows search path, or "" otherwise. Builds an associative -# array auto_execs that caches information about previous checks, +# Windows search path, or "" otherwise. Builds an associative +# array auto_execs that caches information about previous checks, # for speed. # -# Arguments: +# Arguments: # name - Name of a command. if {$tcl_platform(platform) eq "windows"} { @@ -671,7 +866,7 @@ proc auto_execok name { set path "[file dirname [info nameof]];.;" if {[info exists env(WINDIR)]} { - set windir $env(WINDIR) + set windir $env(WINDIR) } if {[info exists windir]} { if {$tcl_platform(os) eq "Windows NT"} { @@ -736,13 +931,13 @@ proc auto_execok name { # This procedure is called by Tcl's core when attempts to call the # filesystem's copydirectory function fail. The semantics of the call # are that 'dest' does not yet exist, i.e. dest should become the exact -# image of src. If dest does exist, we throw an error. -# +# image of src. If dest does exist, we throw an error. +# # Note that making changes to this procedure can change the results # of running Tcl's tests. # -# Arguments: -# action - "renaming" or "copying" +# Arguments: +# action - "renaming" or "copying" # src - source directory # dest - destination directory proc tcl::CopyDirectory {action src dest} { @@ -770,7 +965,7 @@ proc tcl::CopyDirectory {action src dest} { # exists, then we should only call this function if -force # is true, which means we just want to over-write. So, # the following code is now commented out. - # + # # return -code error "error $action \"$src\" to\ # \"$dest\": file already exists" } else { @@ -803,7 +998,7 @@ proc tcl::CopyDirectory {action src dest} { # Have to be careful to capture both visible and hidden files. # We will also be more generous to the file system and not # assume the hidden and non-hidden lists are non-overlapping. - # + # # On Unix 'hidden' files begin with '.'. On other platforms # or filesystems hidden files may have other interpretations. set filelist [concat [glob -nocomplain -directory $src *] \ |