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Rebol [
Title: "Rebmu Dialect"
Purpose: {
Rebol dialect designed for participating in "Code Golf"
Author: {"Dr. Rebmu"}
License: 'mit
Date: 15-Sep-2015
Version: 0.7.0
; Header conventions:
File: %rebmu.reb
Type: module
Name: Rebmu
Level: 'genius
Notes: {
Originally Rebmu tried to define single characters as having values
so you could have "a value of that type around" (x, y, z as 0.0 to
have a float around, s as {} to have an empty string, etc.)
Thought to be helpful for golfing, it turned out to not be THAT
helpful. The trivial puzzles in which that count wasn't lost in the
noise were usually solvable in fewer characters by another language
that was a precise match for the domain of the question. It was
difficult to remember and taught nothing that would be relevant to
Rebol or Red.
So the single character definitions were scaled back drastically.
They are tracked here as an index and to-do list, while the actual
definitions are in the functional group in the code.
The . character was once available but was taken for TUPLE!.
The & character was also once available, but reserved for future use.
~ ; is hardwired as "quasi null", it evaluates to VOID
a ; usually a program argument or a-function variable
c => copy
e => else
f => for ; now more generic
i => if
l => let
m => match
p => print
q => quote
r => return ; only applies in functions, if not in function will QUIT
t => to ; variants like TSW for TO-SET-WORD trumps T for THEN
u => until
w => while
Because there are only so many single characters (unless you start
using Unicode...) the majority of Rebmu function definitions live
in the two-character space. However, refinements follow a system...
so even if it would be *possible* to do APPEND/DUP => AD, such
compression tricks are seen as less consistent than if you have
APPEND => AP and APPEND/DUP => APD. So the two-character space
is the baseline for growing further in a systemic way.
Yet Rebol itself does define a few things already in the two character
space that should not be overridden, to reach Rebmu's goal of being
able to compatibly run any all-lowercase Rebol code in midstream.
Here's a short study of the space used.
Very Reasonable Use of English Words
TO to conversion
AS aliasing operator
OR or operator (infix)
IN word or block in the object's context
IF conditional if
DO evaluates a block, file, url, function word
AT returns the series at the specified index
NO logic false
ON logic true
SO postfix assert (2 = 1 + 1 so print "math works")
AN english pluralize (an "axe" -> "an axe", an "cat" -> "a cat")
ME self-reference after set word (variable: me + 1)
MY variant of ME for non-enfix (block: my append 10)
BE (unused)
BY (unused)
Reasonably non-controversial use of Symbolic Operators
>= true if the first value is greater than the second (infix)
<= true if the first value is less than the second (infix)
!= true if the values are not equal (infix)
<> same function as != despite looking like empty tag
-> lambda function (`x -> [print x]` is `func [x] [print x]`)
<- pointfree function (`<- append b` is `func [x] [append b x]`)
Debug use of "drawing-looking" operators that pop off the page (their
non-English appearance makes them preferable for this purpose instead
of quirkier things like "-- decrements variables")
-- debug dump following variable name and its value
** comment line out
!! breakpoint
++ (unused)
== section header (TBD, currently strict equality)
?? Debug probe a word, path, block or such
Unapplied in Rebol but used in Red for questionable benefit; these are
likely to take on some kind of larger systemic purpose, possibly as
console DSL operations:
<< infix version of prefix shift left
>> infix version of prefix shift right
Deprecated shorthands for terms defined elsewhere, which have been
reclaimed for Rebmu as "free terms" by the rebol-proposals (and should
be removed from the language, existing only in console modes or
RM alias for DELETE
DT alias for DELTA-TIME
LS print contents of a directory
CD change directory
DS temporary stack debug
Several more options were opened up in the two character space by the
so-called "arrow words". They are things like |> and >< etc. These
have experiments but nothing settled down completely.
There are tricks for `/` acting like a WORD! even though it is actually
a path. That opens up some potential space for `//`, `/.`, `./` and
`..` as being operations, but this concept has not been explored.
Several of these freed up with the requirement that ending in a ?
actually return a LOGIC!. The useful function empty? doesn't fit
if E? is EQUAL? and EM? is EMAIL?
A? => and?
B? ; could be... block?
C? ; could be... char?
D? => distinct?
E? => equal?
G? => greater?
H? => head?
I? ; could be... integer?
L? => lesser?
M? => match? ; MM? is mismatch.
N? => negative?
O? => or?
P? => positive?
S? => same?
T? => tail? ; can't be TRUE?, TAIL? is more important
U? => unequal?
V? => value?
X? => xor?
Y? => true? ; (a.k.a. yes?)
Z? => zero?
; Load the modules implementing mush/unmush
import %mush.reb
import %unmush.reb
; Load the library of xxx-mu functions; tricks that are specific to Rebmu
; and would not seriously find their way into Rebol/Red mainline
; NOTE: While originally there was a tendency to be liberal with these,
; they are being excised as they can sort of be seen as interfering with
; Rebmu's main mission, which is to teach/evangelize Rebol dialecting.
; A trick just for the sake of helping win code golf that does not really
; assist with that (or worse, inhibits learning the languages proper)
; should be included sparingly--if at all
import %mulibrary.reb
; returns a block of definitions to include in the context
remap-datatype: function [type [datatype!] shorter [text!] /noconvert] [
stem: head remove back tail to-text to-word type
result: reduce [
load-value unspaced [shorter "!" ":"] load-value unspaced [":" stem "!"]
load-value unspaced [shorter "?" ":"] load-value unspaced [":" stem "?"]
if not noconvert [
append result spread reduce [
load-value unspaced [shorter "-" ":"] load-value unspaced [":" "to-" stem]
return bind result system.contexts.user
rebmu-base-context: make object! compose [
; Though I considered giving the datatypes 2-character names, I decided
; on 3 (so IN! for INTEGER! instead of I!, in order that the test will
; be IN? with I? available for other purposes). This is a decision
; which may be worth revisiting for some types, as INDEX? has become
; INDEX-OF in the language, so I? is free (for instance). Not all
; types will fit in that space, however.
; Shorcuts for datatypes. Establishes both the type and the query functions.
; (so remapping "em" for EMAIL! makes EM! => EMAIL! and EM? => EMAIL?)
(remap-datatype action! "ac")
(remap-datatype block! "bl")
; CHAR! is a "fake type" (meta word), review
(remap-datatype decimal! "dc")
(remap-datatype email! "em")
(remap-datatype error! "er")
(remap-datatype get-word! "gw")
(remap-datatype group! "gr")
(remap-datatype integer! "in")
(remap-datatype pair! "pr")
(remap-datatype percent! "pc")
(remap-datatype logic! "lc")
(remap-datatype map! "mp")
(remap-datatype object! "ob")
(remap-datatype path! "pa")
; LIT-WORD! is a "fake type" (meta word), review
; REFINEMENT! is a "fake type" (meta word), review
(remap-datatype time! "tm")
(remap-datatype tuple! "tu")
(remap-datatype text! "tx")
(remap-datatype file! "fi")
(remap-datatype word! "wd")
(remap-datatype tag! "tg")
(remap-datatype money! "mn")
(remap-datatype binary! "bi")
; there is no "to-blank" operation in Rebol, all other datatypes have it...
(remap-datatype/noconvert blank! "bn")
; These are particularly common and there aren't many commands starting
; with T so aliasing them is useful. May reconsider this later. Also,
; these are special variations that add behaviors for types unsupported
; by Rebol's operators.
t: :to
tw: :to-word-mu
tsw: :to-set-word
tt: :to-text-mu
tc: :to-char-mu
tb: :to-block
ti: :to-integer
; Note: This is done first because its used in later definitions.
; The behavior of FUNCTION and FUNC vs. CLOSURE and CLOS has to do with
; performance optimization, and ideally only the closure and clos
; semantics would exist. Since performance is not the axis of concern
; for Rebmu, it goes with the more expressive construct (and so may
; Rebol3 at some point)
fn: :function-mu
ds: :does
; DX is a variadic branch builder, delegated to by most constructs that
; want to be able to "do more" than just a branch.
dx: func [:args [<opt> any-value! <variadic>]] [
a: take args
if block? a [return does a]
if word? a [
; !!! TBD
d: :dx
; Function dialects in Rebmu employ a method of quoting their arguments
; literally. If not blocks, they are read as *instructions* for what spec
; or body to build. It is a compact dialect for function construction.
fq: :funqtion-mu
; FX is a particularly tweaked version of FQ that pulls from a list of
; helpful memoizations of names for args and locals. It's designed to
; not stomp on common abbreviations like I for IF.
; !!! To be written...
fx: :fq
f: :fx
; Conditionals in Rebmu are less conservative than in Rebol. They are
; willing to handle non-BLOCK! and non-FUNCTION! branches, returning the
; values as-is. For why this is not done in general, see:
; !!! Should they also take isotope forms and treat them as false or pass
; them through without running any brances?
if: :if-mu
i: :if
inz: adapt :if [condition: :condition != 0]
either: :either-mu
ei: :either
un: adapt :if [condition: not to-value :condition]
es: :else
e: :es
th: :then
ao: :also ; AS is a valid language keyword, AL is ALL
sw: :switch
cs: :case
csa: :case/all
lp: :loop ; L is LET
fe: :for-each
fr: :for ; !!! FOR-MU to tolerate more options, so `f x 10 [...]` works
f: :fr
ev: :every
me: :map-each
rme: :remove-each-mu
cy: :cycle
rp: :repeat ; R is RETURN inside a function (globally R acts as QUIT)
; More valuable to have a single character looping construct take U than
; to have UNLESS take it.
ut: :until
ux: macro [] [[until dx]]
u: :ux
w: :while
uz: macro [] [[until .zero?]]
ue: macro [] [[until .equal?]]
ul: macro [] [[until .lesser?]]
ug: macro [] [[until .greater?]]
cn: :continue
br: :break ; BK is BACK
tr: :trap
ct: :catch
am: :attempt
qt: :quit
r: :qt ; inside functions, R is return; this is done to save Q for quote
lt: :let
l: :lt
us: :use
ob: specialize :make [type: object!]
po: :poke
pc: :pick
ap: :append
ir: :insert ; IN, IS, IT are standalone words
irp: :insert/part
ird: :insert/part/dup
tk: :take
mno: :minimum-of
mxo: :maximum-of
se: :select
rv: :reverse
sl: :split
rm: :remove
rl: :replace ; RP is repeat, REPEND is deprecated in Ren-C
rla: :replace/all
rlac: :replace/all/case
rlat: :replace/all/tail
rlact: :replace/all/case/tail
hd: :head
tl: :tail
bk: :back-mu
nx: :next-mu
ch: :change
chp: :change/part
sk: :skip
fi: :find
fis: :find/skip
uq: :unique
pa: :parse-mu
pp: :pre-parse-mu
ln: specialize :reflect [property: 'length]
os: :offset-of ; OF is used in the language
ix: :index-of
ty: specialize :reflect [property: 'type]
t?: :tail?
h?: :head?
m?: :empty?
v?: :value?
fs: :first ; FR might be confused with fourth
sc: :second
th: :third
fh: :fourth ; FR might be confused with first
ff: :fifth
sx: :sixth
sv: :seventh
eh: :eighth ; EI is either, and EG is either-greater
nh: :ninth
tt: :tenth
ls: :last ; override LS list directory? We need SHELL dialect
del: :delete ; If shipping in console, why not use the matching term?
dl: :delete ; Corresponding to the act of protest of changing RM
co: :compose
cod: :compose/deep
mo: :mush-and-mold-compact
jn: :join
re: :reduce
usp: :unspaced
cl: :collect-mu
qo: :quote ; QU is QUIT
q: :qo ; more useful to abbreviate further than Q for QUIT
el: :elide ; ES is ELSE
ad: :add-mu
sb: :subtract-mu
mp: :multiply
dv: :div-mu
dd: :divide
ng: :negate-mu
z?: :zero?
md: :mod
e?: :equal?
lg10: :log-10
lg2: :log-2
; is L2: LG2 worth it, or L+digit be used for something else?
lge: :log-e ; can't do "(L)og (N)atural" as LN, due to LN: LENGTH-OF
; is LE: LGE worth it, or is LE better used or something else?
lg: :lg10 ; Rebmu's 10-fingered-human bias, also shortens LG10 more
; POW is the infix power operator, but infix is sometimes not what you
; want so Rebol also has power as a prefix variant.
pw: :power
; There may be a slight desire to use abbreviated infix logic, as it would
; cause a different evaluation ordering which might be desirable to have
; at no extra character cost. But OR is already a 2-letter word, and XOR
; and AND are only 3-letter. So it's probably better to save AN/AD for
; other purposes (XO/XR less useful...)
; NT is prefix NOT (itself an alias for NOT?), we took N? for NEGATIVE?
a?: :and?
; o?: :or? ; !!! Does not exist, needs to be added
; x?: :xor? ; !!! same
; These operators are the generalized ones, laid out for the day when
; AND/OR/XOR become "conditional"...they work on bitsets etc.
cm: :complement
ic: :intersect
un: :union
df: :difference
ev?: :even?
od?: :odd?
inc: :increment-mu
ic: :inc
dec: :decrement-mu
dc: :dec
g?: :greater?
ge?: :greater-or-equal?
l?: :lesser?
le?: :lesser-or-equal?
se?: :strict-equal?
n?: :negative?
p?: :positive?
sg: :sign-of
y?: :did
n?: :not
mn: :min
mx: :max
; The void-tolerating forms are more useful
ay: :any ; AN is its own word
al: :all
; to-integer (TI) always rounds down. A "CEIL" operator is useful,
; though it's a bit verbose in Rebol as TO-INTEGER ROUND/CEILING VALUE.
; May be common enough in Code Golf math to warrant inclusion.
ce: :ceiling-mu
; Converters end in "-", so for instance "em-" is equivalent to
; TO-EMAIL. I decided that minus signs on the end would indicate
; conversions because this is one place where default Rebol functions
; use a lot of hyphens. The general goal of these functions is
; unlike modifiers, to not change their inputs. It might be nice
; to have some
pr: :print
p: :pr
rd: :read
wr: :write
wrs: :write-stdout ;-- was PRINT/ONLY
pb: :probe
ri: :readin-mu
r: :ri
rl: :read/lines
nl: :newline ; already abbreviated as LF for line feed (?)
tm: :trim
tmt: :trim/tail
tmh: :trim/head
tma: :trim/all
up: :uppercase
upp: :uppercase/part
lw: :lowercase
lwp: :lowercase/part
; Letter and a tilde means "factory". This convention is not in Rebol
; but I thought that even if AR and AI were available for ARRAY and
; ARRAY/INITIAL the use of the tilde would allow the pattern to
; continue for some other things which *would* collide.
; This used to be done with carets, but Christopher Ross-Gill thought
; tildes looked better.
mk: :make
cp: :copy
c: :cp
cpd: :copy/deep
cpp: :copy/part
cppd: :copy/part/deep
; !!! ~ became reserved for use with BAD-WORD!.
; A~: :array
; AI~: :array/initial
; B~: does [copy []] ; two chars cheaper than cp[]
; H~: :to-http-url-mu
; HS~: :to-http-url-mu/secure
; I~: :make-integer-mu
; M~: :make-matrix-mu
; S~: does [copy ""] ; two chars cheaper than cp""
; SI~: :make-string-initial-mu
bn: :blank
st: :set
gt: :get
en: :encode
swp: :swap-exchange-mu
fm: :format
; os: :onesigned-mu
sp: :space
; !!! Predefined character sets are something that has never been fully
; worked out or worked through. They were in the "proposals" module but
; that has been removed. New ideas for BITSET! implementation would allow
; sparse character sets in Unicode at lower cost.
comment [
ws: :whitespace
dg: :digit
dgh: :digit/hex
dghu: :digit/hex/uppercase
dghl: :digit/hex/lowercase
dgb: :digit/binary
lt: :letter
ltu: :letter/latin/uppercase
ltl: :letter/latin/lowercase
; These can be overridden, but are helpful because mushing tries not to
; overload single-symbol/digit terminal semantics, in favor of giving us
; things like +a and a+. We should automatically generate these for all
; single digits, although figuring out special meanings for a0, s0, m0,
; d1 etc. would be a good idea.
e0: func [value] [value == 0]
e1: func [value] [value == 1]
e2: func [value] [value == 2]
; ...
e9: func [value] [value == 9]
a1: func [value] [add-mu value 1]
a2: func [value] [add-mu value 2]
; ...
s1: func [value] [subtract-mu value 1]
s2: func [value] [subtract-mu value 2]
; ...
d2: func [value] [divide value 2]
; ...
m2: func [value] [multiply value 2]
m3: func [value] [multiply value 3]
; ...
p2: func [value] [value ** 2]
; ...
; These operations work particularly well as the source of an assignment
; because of the way that unmushing turns [A+b] into [a: +b]
; Haven't defined them yet... what will this family do?
; These are not easy to assign to in mushed code, because the bias
; gives the symbol to the next word e.g. [A+b] => [a: +b] instead of
; [a+: b].
; Idea is that these modify their arguments to save you from situations
; where you might otherwise have to make things the target of an assignment,
; like [m: add m 2]. Shorter code with a+M2 than Ma+M2, and you also
; are less likely to cause a mushing break. Note that the plus doesn't
; mean "advance" or "add" in this context, LAST+ is actually an
; operator which traverses the series backwards.
a+: :add-modify-mu
; f+: :first+
; s+: :subtract-modify-mu
; n+: :next-modify-mu
; b+: :back-modify-mu
; How strange could we get? Is it useful to do [Z: EQUALS? Z 3] on any
; kind of regular basis? Maybe if you do that test often after but
; don't need the value
=+: :equal-modify-mu
; what about two character functions? can they return different
; things than their non-modifier counterparts?
ch+: :change-modify-mu
hd+: :head-modify-mu
tl+: :tail-modify-mu
sk+: :skip-modify-mu
; While many of the original code-golf specific aspects of Rebmu that
; were imagined were kicked out as useless (as say, compared to throwing
; in a mushed matrix library etc.) this one is still around for study.
; The idea was an operator to be helpful for quickly redefining symbols
; used repeatedly.
; rf[aBCdEF] => rf[a bc d ef] => a: :bc d: :ef
; If you noticed an unusual repeated need for a function you could throw
; that in. Considering the minimal case of rf[aBC] it's 7 characters, which
; is one more than `A: :bc` would be. However, you wind up at a
; close bracket that starts a new mushing point, so it saves on what would
; be a necessary trailing space.
rf: :redefine-mu
; REVIEW: what kinds of meanings might be given to prefix question mark?
export rebmu: function [
code "The Rebmu or Rebol code"
[text! block! file! url!]
/args "argument A, unless block w/set-words; can be Rebmu format [X10Y20]"
/nocopy "Disable the default copy/deep of arguments for safety"
/stats "Print out some statistical information"
/debug "Output debugging information"
/env "Return runnable object plus environment without executing main"
/inject "Run some test code in the environment after main function"
[block! text!]
/output "Implicitly print the output result"
context (void)
case [
text? code [
if stats [
print ["Input Rebmu string was:" length of code "characters."]
code: load code
any [
file? code
url? code
code: load code
all [
'Rebmu = first code
block? second code
] then [
; ignore the header for the moment... just pick offset
; the first two values from code
take code
take code
] else [
print "WARNING: Rebmu sources should start with Rebmu [...]"
; Keep running, hope the file was valid Rebmu anyway
block? code [
if stats [
print "NOTE: Pass in Rebmu as string, not a block."
print "(That will give you a canonical character count.)"
] else [
fail "Bad code parameter."
ensure block! code
code: my unmush
if debug [
print ["Executing:" mold code]
if stats [
print [
"Rebmu as mushed Rebol block molds to:"
length of mold/only code
inject: default [copy []]
if text? inject [
inject: load inject
if not block? inject [
code: to block! inject
inject: my unmush
either args [
either block? args [
args: unmush either nocopy [args] [copy/deep args]
if not set-word? first args [
; assign to a if the block doesn't start with a set-word
args: compose [a: (args)]
args: compose [a: (args)]
args: copy []
; see
; We track the outermost Rebmu context via a variable in the user context.
; This allows us to effectively create a "new" user context holding all
; the Rebmu overrides.
outermost: unset? 'context
if outermost [
context: copy rebmu-base-context
append context spread args
; Rebmu's own behavior replaces DO, no /NEXT support yet
extend context 'do func [value] [
either string? value [
rebmu value
do value
; When we load, we want default binding to override with this context
; over system.contexts.user
rebmu-load: func [source] [
bind load source context
extend context 'load :rebmu-load
extend context 'ld :rebmu-load
bind code context
bind inject context
if env [ ; only asked for the environment (e.g. to debug it)
return context
result: sys.util.enrescue [
do inject
do code
; If we exit the last "Rebmu user" context, then clear it
if outermost [
context: ~
if error? result [
fail result
if output [
print [result]
return unmeta result