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 tclsh 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 load into namespaces that follow thes pattern:


Each name is an item in the name of the package, excuding ycl, which is item 0.

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

Some packages provide a directory named demo, which constains 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.
Given a channel connected to a Tcl interpreter, evaluate scripts in that interpreter.
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.
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.
Returns the name of the coroutine that executed the current coroutine.
Returns a list of the chan of executing coroutines leading to the current coroutine.
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.
Execute return in the calling coroutine.
Suspend the calling coroutine and return its name. when the coroutine is resumed, arguments are passed to return. This provides control over how the coroutine resumes.
Evaluate a script in the calling coroutine, and return the result.

coro interp

package require {ycl coro}
interp name options
Creates a new intepreter coroutine.

The available options are:

init script
Evaluate $script at level #0.

A new interpreter provides the following routines:

add name script
Adds a routine. script is evaluated at level #1 in the coroutine.
Evaluates a script at level #0.
Evaluates a script at level #1.
remove name
Removes a routine.
return args
Returns from the coroutine.

coro call

coro call is a small system that implements synchronous call semantics among coroutines that might be communicating with asynchronous processes.

Calls a ycl coro call coroutine by yielding to it, passing the name of the current coroutine as the final argument. When the coroutine resumes, arguments are passed to return`
Answers a call, storing the name of the caller away in a certain local variable.
Deletes the curent coroutine and signals the caller to break.
Sends a response to the caller and yields until executed again.


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.

dict deep

Retrieve an item from a deep dict.
Merge deep dicts
Pretty-print a deep dict
Set an item in a deep dict


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.


package require {ycl exec}
namespace import [yclprefix]::exec
cexec channel configuration ?arg? ...
Like exec, but performs no translation on redirected input, and allows configuration of the output channel, making it suitable for use with binary data.
eval script
Evaluates a script in a new process and returns the result. The exit status is the return code of the script.
filter ?exec command? script
Invokes a new interpreter and evaluates script in it. Returns a read/write channel connected to the new process. If exec command is provided, it must return a new interactive interpreter.
Invoke a child program and asynchronously handle stdio, stderr, and exit code. See example at [open].


block ?argspec? body ?args?
Like lambda, but also executes immediately.
block {
        db eval {select * from resources} {
                puts [list $path $owner]
call level ?arg ...?
calls args as a command at the given level. Unlikc eval, args are not evaluated as a script.
eset varname args
Execute a args and assign the result to a variable.
upcall ?level? `args
Treats args as a prepared command , finds a routine for a command at the current level, as tailcall does, and executes the command at the specified level, as uplevel does.


Takes the shortest path from the current node to some other node in a graph while keeping track of and avoiding dead ends.


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.

interp main

A script that sets up a coroutine arranges for another script to be evaluated under that coroutine after entering the event loop, and uses the return options of the evaluation as the return value of the program:

 tclsh /path/to/interp/bin/main myscript arg1 arg2

interp process

Manage intepreters as if they were processes, with each interpreter given its own thread.

Evaluate a script in an existing process. Yields to await the result or interruption of the evaluation.
Create a new process and evaluate a script in that process. Options: Keep the process alive after evalution. Provide the name of the process.
Kill an existing process
List running processes


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


See knit.


package require {ycl list}
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.
Given the name of list A and the name of list B, return a list of members of A that are not members of B.
Like foreach, but accepts the names of lists and consumes their contents incrementally. If the lists being operated on are modified in the process, the results are affected. Stops as soon as one list is empty.
Removes common initial whitespace from the items in a list.
Like dedent, but only removes identical whitespace.
An implementation of a deep list. Provides index, insert, is struct, range and set.
Uses one list to filter items from another.
Like foreach, but accepts list names and consumes items from them.
Given the name of list A, assign to that name of A items in A that precede to the final items, which much form the tail B.
Like join, but accepts the name of a list and assigns the result to that name.
Like lappend, but each argument is the name of a value to append to the list.
Like lappend, but each argument is the name of a list of items to append to the list.
Add and remove layers of list structure.
Like lindex, but accepts the name of a list and assigns the result to that name. Each index must be the index of an existing item.
Like linsert, but accepts the name of a list and assigns the result to that name.
Like llength, but accepts the name of a list and assigns the result to that name.
An implementation of a general "sequence" data type. Provides advance, cursor, has, next, peek, and value.
Like lmap, but accepts list names, incrementally consumes those lists, and assigns the result to the first name.
Like lrange, but accepts the name of a list and assigns the result to that name.
Like lreplace, but accepts the name of a list and assigns the result to that name.
Like lreverse, but accepts the name of a list and assigns the result to that name.
Like lsort, but accepts the name of a list and assigns the result to that name.
Merge items in the second list into the first.
Given the name of list A, and the name list B providing an order, orders the items in A according to the indexes in B, and assigns the result to the name of A.
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 names. Alternatively, removes one item from the end of the list and returns it.
Given th name of list A and the name of list B determine whether A is a prefix in B.
Prepend an item to a list.
Given the name of a length and the name of an index, determine whether the index is within range.
Given the name of list A, returns copies of the requested number of items selected randomly from A.
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 and assigns the result to that name.
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 list A and the name of list B, determine whether A constitutes a subset of B.
Given the name of list A and the name of list B, assign to the name of A all the items in A that follow the initial items which must form prefix B.
Like lassign but accepts the name of list A and assigns the result to the name of list A. Returns an error when there are not as many in the A as given variable names.
Given the name of list A, removes initial whitespace from items in A. Unlike string trim, removes only true whitespace.
Given the name of list A, takes items from A, assigns them to the provided names, and assigns the remainder of the items to the name of A. Alternatively, removes one item from A.
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 and assigns the result to that name.
Given the name of list A, remove the item in A a given index, an assign the result to the name of A.
Returns the indices of items in one list that are in another or pass the provided test.
Given the name of list A and the name of list B, return the items in A that are in B. Alternatively, return the items in A that pass the provided test.

list deep

Retrieves an item from a deep list.
Inserts an item into a deep list.
is deep
Determines whether an item in a list is a deep list.
Pretty-prints a deep list.
Applies list sl to a deep list.
Sets an item in a deep list.

list ordered

package require {ycl list ordered}
ensure list name value
Inserts the given value into the right place in the named ordered list if it isn't already there.
insert list name value
Inserts the given value into the right place in the named ordered list.


count value operator
Given a value and an operator that returns the size of a number of units, efficiently counts the units in the value, and returns the nuber of units and their aggregate size, as reported by the operator.
A more concise version of expr. Assigns the result to the provided variable name. If no variable name is provided, $expr is used.

math rand

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.


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.


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 create
Create an ensemble for the given namespace named by the given name relative to the namespace of the caller.
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.
duplicates all variables in a namespace to another namespace
ensemble subcommands
List the currently-available subcommands of a namespace ensemble.
facade .new name object
Creates a new routine named name relative to the namespace of the caller and extends object with a new routine, facade. The new routine acts as an interface to object, making some subset of routines available. When the facade is deleted, the object is also deleted.
object ?name? ?ns?
Creates a new namespace and a new routine named name relative to the caller. When the routine is called, the first argument is the name of a subroutine, which is resolved relative to the namespace of the object and called with the name of the object as its first argument and any remaining arguments after that. Subroutines should not be defined in the namespace of the object, but in a separate namespace which can then be added to the routine lookup list of the object using object extend namespace.

ns public facade interface

The facade routine added to an object by public facade supports the following routines:

add name
Adds the named routine to the facade if it doesn't already exist.
Returns the name of the facade.
remove name
Removes the named routine from the facade if it exists.


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.
const name value
Creates a routine that always returns value.
lambda ?argspec? body ?args?
An implementation of lambda. Returns a command prefix.
Captures the namespace of the caller and returns a command prefix that executes the given commandprefix from that namespace.
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 set}

In the following descriptions, a word that is a single capital letter represents a ycl list list command.

Items in A that are not in B. If $name is provided, creates a ycl coro call routine that produces the resulting items. Otherwise, returns the result as a list.
Determine whether A and B are equal.
Determine whether A is a subset of B.
Returns a ycl coro call routine that produces the remaining items in B after skipping through the initial items, which must correspond to A. Alternatively, return the result as a list.


package require {ycl string}
base encode varname characters
Encodes the sequence of bytes in the named variable using the given list of characters, of which there should typically be some power of 2 up to 256, and stores the result in the named variable. The encoding scheme is that the binary representation of ordinal value of each character in the list represents the next bit sequence. All bit sequences are concatenated in order to produced the encoded value. The number of bits in each sequence, i.e. the base, is derived from the number of characters provided to encode with. In the last encoded character, only enough bits to bring the current bit count to 8 are part of the value.
base decode varname characters
The inverse of base encode. Decodes the sequence of bytes in the named variable using the givn list of characters, and sotres the result in the named variable.
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.
decode stringname ?encoding?
The inverse of encode, below.
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.
encode stringname ?encoding?
converts the the string stored in stringname to encoding, which by default is the system encoding, assigns the result to that stringname, returning an error if stringname can't be faithfully encoded.
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.
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.
A ycl coro call string iterator.
Like string map but the map is a sequence of arguments rather than a list, and the last argument is the name of a string to operate on rather than the string itself, and the result is assigned to that name.
prefix stringvar suffixvar
Extracts from the value stored in the variable named $stringvar the prefix that precedes the suffix in the variable named $suffixvar, and store the result in $stringvar
Convert the backslash character and non-printing characters in $string into \x or \u escaped form. By default each Tcl special character is escaped.
Like string range, but accepts the name of a string assigns the result to that name.
Like regsub, but accepts the name of a string and assigns the result to that name.
regsplit exprs textvar
Splits the value of the variable named variable according to exprs, which may be a branching expression but which must not contain any capturing parenthesis, and assigns resulting to variable.
Like string replace, but accepts the name of a string and assigns the result to that name.
Return an error if the value of the named value not a decimal number.
Like string reverse, but accepts the name of a value and assigns the result to that name.
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.
Like split, but accepts the name of a value and assigns the result to that name.
suffix stringvar prefixvar
Extracts from the value stored in the variable named $stringvar the suffix that follows the prefix in the variable named $prefixvar, and store the result in $stringvar
Like string map but accepts the name of each replacement value and derives a placeholder value from each name. Provides default delimiters, and automatically quotes each replacement value with list.
to hex
Given the name of a value, convert the value to its hexadecimal representation and assign the result to that name.
Like trim, but accepts the name of a value and assigns the result to name.
Like string tolower, but accepts the name of a value and assigns the result to that name.
set a 5
set b 7
set expr {[set a]}
eval [template a b # c {
    set a @[email protected]
    set b @[email protected]
    expr {$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.


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.


count seconds report
Counts in $seconds the things listed in $report, which may be, years, months, days, hours, minutes, seconds, weeks, or weekdays. Each item is calculated using the time remaining from the results of the previous calculation. Returns a list of results in the order they appear in $report. For accuracy, relies on clock for all time calculations.


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


let varname? {inputvar alias?} ...? body
When varname is needed and the variable does not exist or the value of any of the named variables has changed, applies body with values of named variables as arguments and assigns the result to varname. If alias is provided for a variable the value of the variable is aliased to that for the evaluation.


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.