huddle - Create and manipulate huddle object
Huddle provides a generic Tcl-based serialization/intermediary format. Currently, each node is wrapped in a tag with simple type information.
When converting huddle-notation to other serialization formats like JSON or YAML this type information is used to select the proper notation. And when going from JSON/YAML/... to huddle their notation can be used to select the proper huddle type.
In that manner huddle can serve as a common intermediary format.
huddle-format: >
{HUDDLE {huddle-node}}
huddle-node: >
{tag content}
each content of tag means:
s: (content is a) string
L: list, each sub node is a huddle-node
D: dict, each sub node is a huddle-node
confirmed:
- JSON
- YAML(generally, but cannot discribe YAML-tags)
limitation:
- cannot discribe aliases from a node to other node.
The huddle package returns data as a Tcl dict. Either the dict package or Tcl 8.5 is required for use.
Create a huddle object as a dict. It can contain other huddle objects.
Create a huddle object as a list. It can contain other huddle objects.
Almost the same as dict get. Get a sub-object from the huddle object. key can be used to huddle-list's index.
Get a sub-object from the huddle object, stripped.
Almost the same as dict set. Set a sub-object from the huddle object. key can be used to huddle-list's index.
Almost the same as dict remove. Remove a sub-object from the huddle object. key can be used to huddle-list's index.
Merging huddle objects given.
% set aa [huddle create a b c d]
HUDDLE {D {a {s b} c {s d}}}
% set bb [huddle create a k l m]
HUDDLE {D {a {s k} l {s m}}}
% huddle combine $aa $bb
HUDDLE {D {a {s k} c {s d} l {s m}}}
Comparing two huddle objects recursively. When to equal, returns 1, otherwise 0.
% set aa [huddle create a b c d]
HUDDLE {D {a {s b} c {s d}}}
% set bb [huddle create c d a b]
HUDDLE {D {c {s d} a {s b}}}
% huddle equal $aa $bb
1
Appending child elements. When for dicts, giving key/value. When for lists, giving values.
% set aa [huddle create a b c d]
HUDDLE {D {a {s b} c {s d}}}
% huddle append aa a k l m
HUDDLE {D {a {s k} c {s d} l {s m}}}
% set bb [huddle list i j k l]
HUDDLE {L {{s i} {s j} {s k} {s l}}}
% huddle append bb g h i
HUDDLE {L {{s i} {s j} {s k} {s l} {s g} {s h} {s i}}}
The same as dict keys.
The same as llength.
Return the element type of specified by keys. if ?key? is not given, returns the type of root node.
% huddle type {HUDDLE {s str}}
string
% huddle type {HUDDLE {L {{s a} {s b} {s c}}}}
list
% huddle type {HUDDLE {D {aa {s b} cc {s d}}}} cc
string
Stripped all tags. Converted to normal Tcl's list/dict.
dump a json-stream from the huddle-object.
# normal output has some indents. some strings are escaped.
% huddle jsondump {HUDDLE {L {{L {{s i} {s baa} {s \\k} {L {{s 1.0} {s true} {s /g} {s h}}} {L {{s g}}}}} {s t}}}}
[
[
"i",
"baa",
"\\k",
[
1.0,
true,
"\/g",
"h"
],
["g"]
],
"t"
]
# stripped output
% huddle jsondump {HUDDLE {D {dd {D {bb {D {a {s baa} c {s {d
a}}}} cc {D {g {s h}}}}} ee {D {i {s j} k {s 1} j {s { m\a}}}}}}} "" ""
{"dd": {"bb": {"a": "baa","c": "d\na"},"cc": {"g": "h"}},"ee": {"i": "j","k": 1,"j": " m\\a"}}
construct a huddle object from plain old tcl values. spec is defined as follows:
data is simply a string
data is a tcl list of strings
data is a tcl dict of strings
data is a tcl list of lists
data is a tcl list of dicts
data is a tcl dict where the value of key xx is a tcl list
data is a tcl dict of lists data is plain old tcl values
% huddle compile {dict * list} {a {1 2 3} b {4 5}}
HUDDLE {D {a {L {{s 1} {s 2} {s 3}}} b {L {{s 4} {s 5}}}}}
% huddle compile {dict * {list {dict d list}}} {a {{c 1} {d {2 2 2} e 3}} b {{f 4 g 5}}}
HUDDLE {D {a {L {{D {c {s 1}}} {D {d {L {{s 2} {s 2} {s 2}}} e {s 3}}}}} b {L {{D {f {s 4} g {s 5}}}}}}}
if object is a huddle, returns 1. the other, returns 0.
if object is not a huddle, rises an error.
for type-callbacks.
if object is a huddle, returns root-node. the other, returns [list s $object].
% huddle to_node str
s str
% huddle to_node str !!str
!!str str
% huddle to_node {HUDDLE {s str}}
s str
% huddle to_node {HUDDLE {l {a b c}}}
l {a b c}
for type-callbacks.
Create a huddle object from src with specified tag.
% huddle wrap "" str
HUDDLE str
% huddle wrap s str
HUDDLE {s str}
for type-callbacks.
devolving command to default tag-callback
add a user-specified-type/tag to the huddle library. To see "Additional Type".
The definition of callback for user-type.
The callback procedure shuould reply the following subcommands.
only returns a fixed dict of the type infomation for setting the user-tag.
typename of the type
method list as huddle subcommand. Then, you can call [huddle method1 ...]
tag list for huddle-node as a dict. if the type has child-nodes, use "parent", otherwise use "child".
returns a sub node specified by key.
returns stripped node contents. if the type has child nodes, every node must be stripped.
sets a sub-node from the tagged-content, and returns self.
removes a sub-node from the tagged-content, and returns self.
strip must be defined at all types. get_sub must be defined at container types. set/remove shuould be defined, if you call them.
# callback sample for my-dict
proc my_dict_setting {command args} {
switch -- $command {
setting { ; # type definition
return {
type dict
method {create keys}
tag {d child D parent}
constructor create
str s
}
# type: the type-name
# method: add methods to huddle's subcommand.
# "get_sub/strip/set/remove/equal/append" called by huddle module.
# "strip" must be defined at all types.
# "get_sub" must be defined at container types.
# "set/remove/equal/append" shuould be defined, if you call them.
# tag: tag definition("child/parent" word is maybe obsoleted)
}
get_sub { ; # get a sub-node specified by "key" from the tagged-content
foreach {src key} $args break
return [dict get $src $key]
}
strip { ; # strip from the tagged-content
foreach {src nop} $args break
foreach {key val} $src {
lappend result $key [huddle strip $val]
}
return $result
}
set { ; # set a sub-node from the tagged-content
foreach {src key value} $args break
dict set src $key $value
return $src
}
remove { ; # remove a sub-node from the tagged-content
foreach {src key value} $args break
return [dict remove $src $key]
}
equal { ; # check equal for each node
foreach {src1 src2} $args break
if {[llength $src1] != [llength $src2]} {return 0}
foreach {key1 val1} $src1 {
if {![dict exists $src2 $key1]} {return 0}
if {![huddle _equal_subs $val1 [dict get $src2 $key1]]} {return 0}
}
return 1
}
append { ; # append nodes
foreach {str src list} $args break
if {[llength $list] % 2} {error {wrong # args: should be "huddle append objvar ?key value ...?"}}
set resultL $src
foreach {key value} $list {
if {$str ne ""} {
lappend resultL $key [huddle to_node $value $str]
} else {
lappend resultL $key $value
}
}
return [eval dict create $resultL]
}
create { ; # $args: all arguments after "huddle create"
if {[llength $args] % 2} {error {wrong # args: should be "huddle create ?key value ...?"}}
set resultL {}
foreach {key value} $args {
lappend resultL $key [huddle to_node $value]
}
return [huddle wrap D $resultL]
}
keys {
foreach {src nop} $args break
return [dict keys [lindex [lindex $src 1] 1]]
}
default {
error "$command is not callback for dict"
}
}
}
# inheritance sample from default dict-callback
proc ::yaml::_huddle_mapping {command args} {
switch -- $command {
setting { ; # type definition
return {
type dict
method {mapping}
tag {!!map parent}
constructor mapping
str !!str
}
}
mapping { ; # $args: all arguments after "huddle mapping"
if {[llength $args] % 2} {error {wrong # args: should be "huddle mapping ?key value ...?"}}
set resultL {}
foreach {key value} $args {
lappend resultL $key [huddle to_node $value !!str]
}
return [huddle wrap !!map $resultL]
}
default { ; # devolving to default dict-callback
return [huddle call D $command $args]
}
}
}
You can add huddle-node types e.g. ::struct::tree. To do so, first, define a callback-procedure for additional tagged-type. The proc get argments as command and ?args?. It has some switch-sections.
And, addType subcommand will called.
huddle addType my_dict_setting
# create as a dict
% set bb [huddle create a b c d]
HUDDLE {D {a {s b} c {s d}}}
# create as a list
% set cc [huddle list e f g h]
HUDDLE {L {{s e} {s f} {s g} {s h}}}
% set bbcc [huddle create bb $bb cc $cc]
HUDDLE {D {bb {D {a {s b} c {s d}}} cc {L {{s e} {s f} {s g} {s h}}}}}
% set folding [huddle list $bbcc p [huddle list q r] s]
HUDDLE {L {{D {bb {D {a {s b} c {s d}}} cc {L {{s e} {s f} {s g} {s h}}}}} {s p} {L {{s q} {s r}}} {s s}}}
# normal Tcl's notation
% huddle strip $folding
{bb {a b c d} cc {e f g h}} p {q r} s
# get a sub node
% huddle get $folding 0 bb
HUDDLE {D {a {s b} c {s d}}}
% huddle gets $folding 0 bb
a b c d
# overwrite a node
% huddle set folding 0 bb c kkk
HUDDLE {L {{D {bb {D {a {s b} c {s kkk}}} cc {L {{s e} {s f} {s g} {s h}}}}} {s p} {L {{s q} {s r}}} {s s}}}
# remove a node
% huddle remove $folding 2 1
HUDDLE {L {{D {bb {D {a {s b} c {s kkk}}} cc {L {{s e} {s f} {s g} {s h}}}}} {s p} {L {{s q}}} {s s}}}
% huddle strip $folding
{bb {a b c kkk} cc {e f g h}} p {q r} s
# dump as a JSON stream
% huddle jsondump $folding
[
{
"bb": {
"a": "b",
"c": "kkk"
},
"cc": [
"e",
"f",
"g",
"h"
]
},
"p",
[
"q",
"r"
],
"s"
]
now printing.
This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category huddle of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.
Copyright © 2008 KATO Kanryu <kanryu6@users.sourceforge.net>