activestate smooth transitions using tcl 8.5 and upgrading to tcl 8.6

Smooth Transitions:Using Tcl 8.5 and upgrading to Tcl 8.6

Jeff HobbsDirector of EngineeringActiveState Software Inc.

Agenda

About ActiveStateTcl 8.5 overviewTcl 8.5 features in depthTcl 8.6 overview

ActiveState Solutions

ActiveState and Tcl

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Tcl 8.5

Finished after almost 4 years in development8.5a1 released March 20048.5.0 final December 20078.5.8 released November 20098.5.9 release ETA September 2010

Change in state of stable and beta8.4.19 last community-based released in April 20088.6a1 development initiated April 2008

Tcl 8.5 changes

Over 90 new TIPs included in Tcl 8.58.5 is 99.99% backwards compatible with 8.4 at the Tcl level

Exceptions are in error casesincr auto-initializeNo more integer overflow

Bytecodes have changed - watch version compatibilityActiveTcl tbcload can load 8.4 bytecodes in 8.5

Tcl 8.5 expand and dict

New {*}$aList expansion operatorReplacement for oft-misused eval eval exec [auto_execok start] [list $url]=> exec {*}[auto_execok start] $url

New dict data structureOrder-preserving key/value pairs kept as Tcl_ObjsMore efficient and nestableClose pairing with [array get] and listsCan replace any use of TclX keyed listsNumerous subcommands for filtering, updating dataSome operations byte-coded8.4 emulated version in ActiveTcl

Tcl 8.5 expr

New expr operators** (exponentation), min, max, isqrt, bool, entierin (in list) expr {“b” in {a b c}} => 1ni (not in list), replaces use of lsearch != -1

New ::tcl::mathfunc namespace for functionsDefine expr functions at the Tcl level

New ::tcl::mathop namespace for operationsAllows importing as commands for prefix mathAll functions are byte-compiled

No more integer overflow because of bignums

Tcl 8.5 bignumsexpr 2 ** 1024179769313486231590772930519078902473361797697894230657273430081157732675805500963132708477322407536021120113879871393357658789768814416622492847430639474124377767893424865485276302219601246094119453082952085005768838150682342462881473913110540827237163350510684586298239947245938479716304835356329624224137216

Every single bit hand-verified by Kevin KennyWork continuing on performance of bignumsBignums available for all expressions, but most indexing is still limited to 32-bit values (ie: string index, lindex)Floating point handling improved to reduce rounding errors

Tcl 8.5 list ops

Added lrepeat, lassign, lreverselassign is as taken from TclXlrepeat number element1 ?element2 element3 ...?

Extended lsort, lsearchlsearch -index -nocase -subindiceslsort -nocase -indices

List indices now support int[+-]int and end[+-]int syntax

Tcl 8.5 namespaces

namespace ensemble (ensemble commands)Adopted from [incr Tcl], useful for subcommand-style procedures[::carrot::foo] == [::carrot foo]

namespace unknown (per-namespace unknown control)namespace path (name resolution control)namespace upvar (namespace var efficiency)

Tcl 8.5 clock

Completely revamped clock command64-bit, new parser, ensemble-basedNo more Y2038 issues, even on 32-bit systemsFull localization support

Several new subcommandsclock add

Simplifies date math operationsclock microseconds|milliseconds

Improved resolutionClock scan and format updated

User-specifiable scan formatsFull set of Olsen timezone data

Tcl 8.5 interp

Resource limiting with interp limit commandTime and command count based

Improved background error handling with interp bgerrorEnhanced debugging with info frame

Returns current command location and informationUnderstands origin (source, proc, eval, precompiled)

New chan command to consolidate channel operations

Subsumes most f* file id manipulation commandsChannel reflection exposed at the Tcl level (chan create)chan truncate added

Tcl 8.5 packaging

Enhanced package versioningUnderstand a, b designation in version number (8.5a5)Allow for bounded version rangesControl preference for stable or latest version available

Tcl Modules (.tm) package handlingIntended to improve packaging long term

tclsh and source -encoding optionencoding dirs

Tcl level control of where to find encodings

Tcl 8.5 extras

Enhanced catch and returnMake pure Tcl control structures more powerful

New apply operator for anonymous procedures (lambda)apply {x {expr {$x*$x}}} 5 => 25

Several new binary format codes and improved unsigned value support%t (tiny/short), %n (normal/int), %m (wide), %r/R (single precision real), %q/Q (double precision real), %u (unsigned)

scan and format have %llx modifiersNew tcl_platform(pointerSize) element

Tcl 8.5 switch and string

switch -regexp can provide submatch information

switch -matchvar foo -indexvar bar -regexp -- $string { {\w*(e)\w*} { puts "matched [lindex $foo 0] with 'e' at \

[lindex $bar 1 0]" } ...

switch added a -nocase optionNew string is list|wideinteger classificationsNew string reverse subcommand

Tcl 8.5 gotchas

global varName(elemName) raises an error nowAlso for upvar 0 x(1) y(1)Was previously an impotent operation that created inaccessible variables

Don’t rely on integer overflow - shouldn’t happenlist properly quotes the # chartcl_precision now defaults to 0Auto-initialize for incr

Previously an undefined var would cause an errorGains semantic parity with append, lappend

Tcl 8.6

Currently in active development8.6a1 development initiated April 20088.6b1 released December 20088.6b2 release ETA October 2010

Release schedule marching towards final8.6.0 targeted for 2011

Over 40 TIPs implemented for 8.6Community driven input

Tcl‘2010, October 2010 in Chicagohttp://www.tcl.tk/community/tcl2010/

Tcl 8.6 OO

Core OO! (TIP#257,#320)Major effort by Donal FellowsFoundational OO system inspired by XOTcl and snitProvided in core (no package)oo::class, oo::define, oo::copy, oo::object, ...Class-based object system with dynamic redefinition allowedPer-object customization with filters, mixins and moreHas C API to create and manage classes, instances and methods

% oo::class create example { variable foo constructor {{value 10}} { set foo 0 my bar $value } destructor { } method bar {input} { incr foo $input }}=> ::example% example create b 4=> ::b% b bar 3=> 7

Tcl 8.6 highlights

Next version of [incr Tcl] (v4) uses TclOONew non-recursive bytecode engine

Enables coroutines, aka generatorsTcl level coroutines in development

Proper tailcallsLess stack hammeringC API to allow user commands to be restartable

Simplified Tcl prefix matchingC API for option parsing taken from Tk as well

Thread extension to be included with core sourcesOther extensions being considered

Tcl 8.6 features

New binary encode|decode with base64binary is now a namespace ensemble

Ability to cancel script evaluation via interp cancelFind insertion point in sorted list lsearch -bisectAdded tcl_platform(pathSeparator) keyUnicode aware string trim*Grouped sort with lsort -strideAllow lset to extend listslset myList end+1 foo equivalent to lappend myList foo

More 8.6 stuff!

Many commands accept nothing gracefully (TIP#323)Base-2 support in format and scan with %bNew file tempfile ?nameVar? ?template?

Creates tempfile and returns a channelNew try/finally syntaxtry body ?handler...? ?finally script?

set f [open $file a]try { puts $f "oops ..." # ...} finally { close $f}

try { set f [open $file]} trap {POSIX EISDIR} {} { puts "failed to open $file: it's a directory"} trap {POSIX ENOENT} {} { puts "failed to open $file: it doesn't exist"}

But wait, there’s more!

Zlib compression included with new core zlib command

Builds on standard zlib sourcesFull zip and unzip support for gzip and zlib formatsSupports channel streaming for transformsIncludes adler32 and crc32 checksummingIncludes Tcl_Zlib* C API

Enhanced chan commandclose can close only read or write sideAnonymous pipes with chan pipeTcl level channel transformations chan push|pop

And on the C side of 8.6

Make Tcl_Interp opaqueNo more interp->result

Use Tcl_GetStringResult(interp) insteadAPI for interp->errorLine

Access to startup scripts from CTcl_Obj *Tcl_GetStartupScript(const char **encodingNamePtr)void Tcl_SetStartupScript(Tcl_Obj *pathPtr, const char *encodingName)

Portable Tcl_StatBuf accessTcl_Get*FromStat

Tcl 8.6 TDBC

Standard interface for database connectorsCurrently has drivers for sqlite, mysql, odbc and postgres

Leverages TclOO frameworkpackage require tdbc::sqlite3

tdbc::sqlite3::connection create db "phonebook.sqlite3"

set statement [db prepare {

SELECT phone_num FROM directory

WHERE first_name = :firstname

AND last_name = :lastname

}]

db transaction { set firstname "Fred" set lastname "Flintstone"

$statement foreach row { puts [dict get $row phone_num] }}

$statement closedb close

In summary ...

8.5 is 99% compatible with 8.4 at Tcl levelStable and ready for all task loads

8.6 currently in betaFinal release ETA 2011Lots of new features, with more to comeFurther discussion at Tcl‘2010, October 2010 in Chicago

http://www.tcl.tk/community/tcl2010/

Tcl Dev Kit and Komodo support both 8.5 and 8.6Later 8.6 changes may require further updates

Q & A

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