ycl , short for Yorick's Computing tooLkit, is PYK's collection of miscellaneous procedures and programs.


To download ycl:

fossil clone http://chiselapp.com/user/pooryorick/repository/ycl ycl.fossil

Then, open the fossil and add /path/to/opened/fossil/packages to $auto_path

There is also a helper script, .../ycl/bin/yclrun, which will automatically adjust $auto_path, and can be used as wrapper:

tclsh /path/to/opened/fossil/packages/ycl/bin/yclrun myscript.tcl

There is another helper script for an interactive shell:

tclsh /path/to/opened/fossil/packages/ycl/bin/yclsh

Zipguy 2013-11-24: How about if you put all those files into a folder structure? Even one folder, named 'ycl', or 'app-ycl' would work good. Then you could either zip them (or you could have gz'ed them), or SDX them (into a starkit) which would make it a lot easier to download them? There are way too many files for me to chase, individually, even though they look quite interesting. Probably a version would be good too, so you could check it, and see if you've already downloaded the latest version.

pyk: you can get this by logging into the repository as anonymous, and then choosing to download the zip or tarball for the commit you're interested in.


The documentation appears in the source code immediately prior to each function declaration. It is in a text format which is intended to be reasonably intuitive even without much knowledge of Tcl.

Most packages have test suites (look for files ending in .test), which provide examples.


The script ycl/bin/ycl can be used to call a command in ycl from a shell.


ycl/bin/ycl cmd package command ?args?

command is a command available in package


From an sh shell:

$ tclsh /cygdrive/c/Users/yorick/Documents/ycl/src/packages/ycl/bin/ycl cmd 'math rand' randprint_256
BUV9z#[email protected]^ytLk1LrTKRp35tbqN^LgqkH7Z6



Connect the output of one channel to the input of another. Uses a separate thread to avoid deadlocks.
osin chan
Using chan pipe, creates an os channel to feed $chan, and returns the writable end of the pipe, configured to -translation binary -blocking 0. Useful, for example, with exec where only real os channel can be used in a redirection.
osout chan
Using chan pipe, creates an os channel fed by $chan, and returns the readable end of the pipe, configured to -translation binary -blocking 0.
both chan
osin and osout combined. Returns a readable channel and a writable channel, both configured to -translation binary -blocking 0.
   to give an existing channel a facade composed of actual os channels.  Useful, for example, to use a [reflected channel] in an `[exec]` redirection.  The new channels are configured to `-translation binary` and the configuration of the original channel is unchanged.  To read from the new channel instead of using it in an `[exec]` redirection, configure the original channel to `-translation binary` after obtaining the new channel, and configure the new channel as desired.
Transforms a channel into another channel whose output is asynchronously duplicated to a third channel.
A reflected channel that wraps another channel, translating its contents from HTTP chunked format. Written as a reflected channel instead of a channel transform so that the wrapped channel can persist after the chunked wrapper is closed. This feature is useful for persistent HTTP connections.
clib pushTransform
A Critcl C function that can be used by another Critcl package to push a channel transform onto a channel:
package require {ycl chan clib}
critcl::api import ycl_chan_clib
critcl::cproc someproc ... {
        pushTransform(..., mytransform ...)

The signature for pushTransform is:

int pushTransform(Tcl_Interp interp
        ,ClientData clientData
        ,ycl_chan_transform_eofProc eof
        ,ycl_chan_transform_closedProc closed

The transform routine has the following signature:

int transform(Tcl_UniChar uchar ,Tcl_DString output)

It is called once for each character encountered while reading the channel, and should append the transformation to ˇoutputˇ. The transform routine can maintain its own state and append to output each time it receives enough meaningful information to complete the next piece of the transformation.

A skeleton reflected channel that wraps another channel.

chan clib

package require {ycl chan clib}
::critcl::api import ycl_chan_clib 0.1

Provides the following C functions:

filter(Tcl_Interp *interp ,Tcl_Channel inchan ,Tcl_Channel outchan ,(process)(Tcl_Interp *interp ,Tcl_UniChar *uchar ,Tcl_DString *output))
Filters data as it passes from inchan to outchan. process recieves one character and modifies output , which is then written to outchan.


ycl comm http
An http client that makes use of coroutines and reflected channels.


Deprecated in favor of ycl shelf

package require {ycl context}
namespace import [yclprefix]::context::context

proc fly {ns args} {
    puts  "$ns is flying!"

proc nofly {ns args} {
    puts "$ns can't fly!"

context bird
bird method fly
bird fly

bird derive eagle
eagle fly

bird derive emu
emu method fly nofly
emu fly

#remove emu's restriction
set emumethods [namespace ensemble configure emu -map]
set emumethods [dict remove $emumethods fly]
namespace ensemble configure emu -map $emumethods

emu fly


async: A distillation of the ycl coro relay system into three commands
wait, reply, and async. This provides all the functionality of Javascript promises but without all the extra syntax.
An event loop for coroutines. Tries to play nice with Tcl's event loop. This system was created to avoid the performance penalty of using Tcl's event loop as a queue for communication between coroutines.
A small but complete system that allows cooperating coroutines to make and deliver orders amongst themselves.


An entity-attribute-value system built on sqlite, featuring a Tcl-ish interface and query capabilities, and traces for maintaining data constraints and reacting in other ways to record updates.


creates and manages minions of threaded asynchronous pipelined backpressure-mediated compute stations.


Like lsearch, but searches keys, and returns results in reverse order.
Like dict set, but doesn't deduplicate other keys in the dictionary.
Like dict unset, but doesn't deduplicate other keys in the dictionary.


package require {ycl dir}
namespace import [yclprefix]::dir
Copy a file or directory into an archive location, faithfully duplicating any symbolic links, recursively, in the path of the file. Does not copy the contents of a directory, just the directory node itself, which may be a symbolic link. In order to accomodate arbitrary symbolic links in the path of the file or directory, It is placed in the archive at the same absolute location, with the archive directory as the root.
find duplicate files
remove duplicate files
iterate over items in a directory tree.
for item in [dir iter /my/dir] {
    #do stuff
A drop-in replacement for glob that provides a new type specifier, +hidden, to include hidden files all results.


A "daemon" coroutine that collects entropy when the system is idle.


filter ?exec command? script
Invoke a new interpreter and evaluate script in it. Returns a read/write channel connected to the new process. If exec command is provided, it must return a new ineractive interpreter.
invoke a child program and asynchronously handle stdio, stderr, and exit code. See example at [open].


Very similar in spirit to Generator. Can be used with [for ... in]

package require {ycl iter}

A set of iterators

iterate over a file, by line or arbitrary function
iterate over the characters in a string


converts the words of a value in sh syntax to a Tcl list.


package require {ycl iter for}
for ... in
a convenient loop construct for working with iterators


See knit.


Like lappend, but only adds the item if it isn't in the list.
Like add, but prepends the item.
Returns true if all the items in one list are in another or pass the provided test.
Returns true if any items in one list are in another or pass the provided test.
Returns a list of indices of items that are in another list or pass the provided test.
Uses a provided function to determine whether two lists are comparble.
Removes common initial whitespace from the items in a list.
Like dedent, but only removes identical whitespace.
Uses one list to filter items from another.
Like foreach, but accepts list names and consumes items from them.
Like join, but accepts the name of a list and assigns the result to that name.
Add and remove layers from nested lists.
Like lreplace, but accepts the name of a list and assigns the result to that name.
Merge items in the second list into the first.
Pick certain elements from a list by index or by range, with an optional step.
Given the name of a list, removes items from the list and assigns them to the provided variable names. Alternatively, removes one item from the end of the list and returns it.
Prepend an item to a list.
Returns a random index of an item in a list.
Reorders a list according to a given list of indices.
Like lindex, but returns an error when an index is out of bounds.
scripted list.
Like split, but accepts the name of a list.
A building block of sl. Takes one argument, treats it as a script, splits it into commands,
                discards comments, performs substitutions on the words in the commands,
                and returns a list of the commands.
Given the name of a list, removes initial whitespace from items in the list. Unlike string trim, removes only true whitespace.
Given the name of a list, takes items from the list, assigns them to the provided variable names, and assigns the remainder of the items to the original name. Alternatively, removes one item from the list.
Removes duplicate items in a list without sorting it.
Like lassign, but produces an error if there are not enough items to assign to the provided names.
Like unpack, but accepts the name of a list.
Unset an index in a nested list.
Returns the indices of items in one list that are in another or pass the provided test.


A close-to-drop-in replacement for tcllib's matrix, but with better performance characteristics since it's more careful about avoiding duplication of data during operation.


Randomly produces a 1 or 0. The output is intended to have the same high entropy as as true random numbers and to be suitable for cryptographic use. This command is analagous to /dev/random.
Cryptogphic random number generator using a seed produced by flip. Analagous to /dev/urandom.
A cryptographically-strong alternative to the built-in rand() function.


package require {ycl ns}
Copy all commands in a namespace to another namespace, refusing to overwrite any existing commands, and ignoring commands named in in $args. In contrast to oo::copy <cloned>, if a command is both an alias and a procedure, it is treated as an alias.
ensemble duplicate
Copy a namespace ensemble, and if necessary, the namespace that's backing it, along with any child namespaces, recursively. Also replaces in the ensemble map occurrences of the old ensemble name with the new ensemble name. dupensemble can be used as the simplese form of object system, where each namespace hierarchy is treated as an object. Tcl's copy-on-write semantics make this system much more efficient than one would expect at first blush. dupensemble is used by ycl::shelf
Resolve and call a command in some namespace without adding a level like namespace eval does.
ensemble subcommands
List the currently-available subcommands of a namespace ensemble.
duplicates all variables in a namespace to another namespace


like package vcompare, but accepts just about anything as a version string.


tcl commands
Split a Tcl script into its components. This is scriptsplit
tcl iter
Uses ycl coro relay to deliver the comands in a script read from a channel.
tcl words
Split a Tcl command into its components. This is cmdSplit.
tcl wordparts
Split a logical word from a Tcl command into its literal, escape-sequence, and substitution components. This is wordparts.
tcl stream
Incrementally parse a Tcl script from a channel.
An xml parser based on ycl parser graph. -relax true enables a forgiving mode when trying to make it through an document.
xml util validCharExpr varname
Returns an expression that evaluates to true if the character in $varname is a valid XML character, and false otherwise.
xml util encodeInvalidChars inchanname outchanname
A filter between channels that converts characters that are invalid in XML to their XML character representations. Accelerated with Critcl when it's available. Uses ycl chan clib filter.
xml util chanEncodeInvalidChars
A stacked channel that encodes invalid XML characters into character entities. Uses ycl chan clib pushTransform.



package require {ycl parser graph}
A framework for extracting graphs from data. -transient false instructs the parser to leave behind a hierarchy of namespaces representing the graph, and commands like children, path, and traverse provide an interface to the graph. This system facilitates the creation of parsers that ignore text outside the target syntax of a given parser.
Adapted from Config file using slave interp.


package require ycl::dir
namespace import [yclprefix]::dir
functional documentation for procedures. Somewhat like tepam, with additional aspects of literate programming. Examples include ycl::dir::iter , and ycl::ns::object
an analogue of interp alias that avoids the potential negative performance impact. In contrast to interp alias, extra arguments can not be tacked on to the alias.
Like proc, except that the body is a list of lists and no string representation of the body is generated.
tcl step
A drop-in replacement for proc that provides a pre-evaluation hook and an error handling hook for each command in the script.



See ycl shelf


package require {ycl string}
Like the Unix cmp command, compares two strings and returns the index at which they differ, or -1 if they are identical. Uses a bisect strategy for performance, and for memory efficiency does not extract substrings. Short-circuits when a difference is found.
Determines whether a value is a decimal number
Determines whether a value is a number as understood by expr, except that a leading zero does not signify an octal number.
Like string match, but returns -1 if $string doesn't match, and the index of the last char of the shortest match if it does.
Removes common newline-whitespace, taking tabs into consideration.
Removes common whitespace.
split (partition) a string into substrings using any combination of string, match, or regular expressions, returning both the substrings and the delimiters.
Provides a concise syntax for embedding and expanding templated text, the primary target being Tcl scripts. One unusual feature is that operators are embedded in the chunks of text they operate on. Based on ycl parser graph.
Cut down the verbosity of string map by using the same name to obtain a value from a local variable and to map that value into the string, providing default delimiters, and by automatically quoting values with list. Example:
set a 5
set b 7
set expr {[set a]}
eval [template a b # c {
        set a @[email protected]
        set b @[email protected]
        expr {$a + $b + @[email protected]}


create, savigate, and manipulate hierarchical data structures. Implemented over tDOM.
Nested heterogeneous structures. Example: nxs get $mystruct l {0 3 1} d {name Bob friends} l 5. To set a nested vale: nxs set mystruct l {0 3 1} d {name Bob friends} = l end Jane. Extend the functions to additional types of nested structures by adding keys to nxs::get, nxs::set, and nxs::unset. To specialize the library, use ycl ns dupensemble to create a copy of it.


block ?argspec? body ?args?
Like lambda, but also executes immediately.
block {
        db eval {select * from resources} {
                puts [list $path $owner]
lambda ?argspec? body ?args?
An implementation of lambda. Returns a value that can be used as a command prefix.


Like switch, but each pattern is a list of patterns to match against the item in string at the corresponding position. All switch options are supported.


Returns the current namespace to the state it was in before the test was run.


test sometest {} -body {
} -cleanup [cleanup1] -result ...


Formats a string as a printable Tcl string. Non-printable characters are transformed into their most simple backslash-escaped representation, and backslash is also escaped.


Assimilated from Bryan Okley's combobox.


Together with proc::methods, proc::upmethods, and var::upmethods, compromises an object system much like ycl::context. Its method calling style provides for uplevel 1 to be the object's namespace, and uplevel 2 to be the caller of the method. This turned out to be a little clunky, and ycl shelf is now preferred to this system.

#! /bin/env tclsh

package require ycl::ns
namespace import ycl::ns::object
package require ycl::proc

namespace import ycl::proc::*method

upmethod die {} {} {} {
    puts "$_ dies."

object chessman import {name die}
chessman $ name unknown

namespace eval chessman {
    upmethod move {} {} {} {
        puts "$_ doesn't know how to move!"

object pawn
pawn parent chessman
namespace eval pawn {
    upmethod move {} {} {} {
        puts "$_ is plodding forward"

object knight 
knight parent chessman
namespace eval knight {
    upmethod move {} {} {} {
        puts "$_ gallops forward and to the side"

object amazon
namespace eval amazon {
    upmethod move {args} {} {} {
        dict with args {}
        if {$as ni {knight queen}} {
            puts "$_ can not move as a $as"
        } else {
            puts "$_ is moving as a $as"

puts "chessman name is: [chessman $ name]"
# -> unknown

chessman move
# -> ::chessman doesn't know how to move! 

object pawn1 
pawn1 parent pawn
pawn1 move 
# -> ::pawn1 is plodding forward

puts "pawn1 name is: [pawn1 $ name]"
# -> unknown

pawn1 $ name {white a}
puts "pawn1 name is now: [pawn1 $ name]"
# -> white a

object knight1
knight1 parent knight
knight1 move 
# -> ::knight1 gallops forward and to the side 

object knight3
knight3 parent knight2
knight3 parent amazon
knight3 move as queen
knight3 move as bishop


A simple presentation system in Tk.

anonymous - 2016-08-26 01:25:05

What is the license on your ycl toolkit? It's not totally clear and there are some GPL'd items hidden in it.

PYK 2016-08-30: Contributors license their contributions independently. As for my contributions, I'm currently handling license requests on a case-by-case basis.