The "Unknown:"s below indicate that an entry is incomplete.

• either the entry exist in the language, and please tell.
• either the entry doesn't exist in the language, and please tell so. The entry will be marked as such and won't appear as missing anymore.

• Category: Object Oriented, Dynamically typed

• Various

  nothing needed	breaking lines (useful when end-of-line and/or indentation has a special meaning)
  { ... }	commenting (nestable)
  comment { ... }	commenting (nestable)
  comment [ ... ]	commenting (nestable)
  [ ... ](1)	commenting (nestable)
  ;	commenting (until end of line)
  < > <= >=	comparison
  min / max	comparison (min / max (binary or more))
  rebol [ Note: "..." ]	documentation comment
  func ["..." arg] ...	documentation comment
  = <>	equality / inequality (deep)
  = <>	equality / inequality (shallow)
  recycle	force garbage collection
  ( ... )	grouping expressions
  [ ... ]	grouping expressions
  system/script/header/file(2)	information about the current line and file
  do / reduce / compose / load	runtime evaluation
  case-insensitive	tokens (case-sensitivity (keywords, variable identifiers...))
  [_a-zA-Z?!.'+*&|=~-][_a-zA-Z0-9?!.'+*&|=~-]* or [^0-9[](){}":;/][^ \n\t[](){}":;/]*	tokens (variable identifier regexp)
  hyphens	tokens (what is the standard way for scrunching together multiple words)
  :	variable assignment or declaration (assignment)
  set	variable assignment or declaration (assignment)

• Functions

  func [a b ...] ...	anonymous function
  f a b ...	function call
  f	function call (with no parameter)
  f: func [para1 para2 ...] ...	function definition
  return(3)	function return value (breaks the control flow)
  no syntax needed(4)	function return value (function body is the result)

  Unknown:

  runtime inspecting the caller information

• Control Flow

  / break/return	breaking control flow (continue / break)
  return(3)	breaking control flow (returning a value)
  catch	exception (catching)
  catch/name	exception (catching)
  throw	exception (throwing)
  throw/name	exception (throwing)
  if c ...	if_then
  either c b1 b2 / if/else c b1 b2	if_then_else
  until [... c]	loop (do something until condition)
  forever	loop (forever loop)
  while [c][...]	loop (while condition do something)
  switch val [ v1 [...] v2 [...] ] switch/default [ v1 [...] v2 [...] ][...]	multiple selection (switch)
  space	sequence

  Unknown:

  loop (for each value in a numeric range, 1 increment (see also the entries about ranges))
  loop (for each value in a numeric range, 1 decrement)
  loop (for each value in a numeric range, free increment)
  breaking control flow (goto (unconditional jump))

• Types

  make t e / to t e

  cast (computed conversion (calls an internal or a user-defined function))

• Object Oriented & Reflexivity

  self	current instance
  all [in object 'method function? get in object 'method]	has the method
  make parent ...	inheritance
  object/method para	method invocation
  object/method	method invocation (with no parameter)
  make o []	object cloning
  make class_name! ...	object creation

  Unknown:

  manually call an object's destructor
  class declaration
  testing class membership
  get the type/class corresponding to an object/instance/value
  methods available
  accessing parent method

• Package, Module

  do	import (everything into current namespace)

  Unknown:

  package scope
  declare

• Strings

  s/:n	accessing n-th character
  to char! / to-char	ascii to character
  #"z"	character "z"
  to integer! / to-integer	character to ascii
  char!	character type name
  to string! / to-string / to ""	convert something to a string (see also string interpolation)
  insert/dup	duplicate n times
  copy/part at s n len	extract a substring
  copy/part at s n at s m	extract a substring
  find	locate a substring
  find/last	locate a substring (starting at the end)
  {...}	multi-line
  print(5)	simple print (on any objects)
  prin	simple print (on any objects)
  append	string concatenation
  length?	string size
  "^/"	strings (end-of-line (without writing the real CR or LF character))
  "..."	strings (with no interpolation of variables)
  string!	type name
  uppercase form / lowercase form	upper / lower case character
  uppercase/lowercase	uppercase / lowercase / capitalized string

  Unknown:

  strings (with interpolation of variables)
  serialize (marshalling)
  unserialize (un-marshalling)
  sprintf-like
  string equality & inequality

• Booleans

  false	false value
  none	false value
  not(6)	logical not
  or / and	logical or / and (non short circuit (always evaluates both arguments))
  any / all	logical or / and (short circuit)
  true	true value
  anything not false	true value
  logic!	type name

• Bags and Lists

  insert	adding an element at the beginning (list cons) (side-effect)
  append	adding an element at the end (side-effect)
  find	find an element
  first	first element
  foreach	for each element do something
  last	last element
  append	list concatenation
  [ a b c ]	list constructor
  length?	list size
  a/:i	list/array indexing
  select	lookup an element in a association list
  unique(7)	remove duplicates
  reverse	reverse
  minimum-of / maximum-of	smallest / biggest element
  sort(8)	sort

  Unknown:

  list flattening
  adding an element at index
  all but the first element
  get the first element and remove it
  get the last element and remove it
  is an element in the list
  join a list of strings in a string using a glue string
  iterate with index

• Various Data Types

  a . b . c	tuple constructor
  tuple!	tuple type

  Unknown:

  computable tuple (these are a kind of immutable lists playing a special role in parameter passing) (empty tuple)
  computable tuple (these are a kind of immutable lists playing a special role in parameter passing) (1-uple)
  computable tuple (these are a kind of immutable lists playing a special role in parameter passing) (using a tuple for a function call)
  reference (pointer) (creation)
  reference (pointer) (dereference)
  optional value (null value)
  optional value (value)
  optional value (null coalescing)
  record (selector)
  dictionary (constructor)
  dictionary (access)
  dictionary (has the key ?)
  dictionary (remove by key)
  dictionary (list of keys)
  dictionary (list of values)
  dictionary (merge)
  range

• Mathematics

  and / or / xor	bitwise operators (and / or / xor)
  complement	bitwise operators (bitwise inversion)
  **	exponentiation (power)
  power	exponentiation (power)
  log-10	logarithm (base 10)
  log-10 / log-2	logarithm (base 2)
  log-e	logarithm (base e)
  //	modulo (modulo of -3 / 2 is -1)
  -	negation
  negate	negation
  1000., 1E3, 1,0	numbers syntax (floating point)
  1'000, 10'00, 100'0	numbers syntax (integer thousand-separator)
  2#{1}, #{F}	numbers syntax (integers in base 2, octal and hexadecimal)
  1000	numbers syntax (integers)
  square-root / exp / abs or absolute	square root / e-exponential / absolute value
  sine / cosine / tangent	trigonometry (basic)
  arcsine / arccosine / arctangent	trigonometry (inverse)
  to-integer / / /	truncate / round / floor / ceil

  Unknown:

  addition / subtraction / multiplication / division
  random (random number)
  random (seed the pseudo random generator)
  operator priorities and associativities

Remarks

• (1) when unused
• (2) need "file: %script-header.r" in file header
• (3) in Lua, "return xxx" can only appear before a block end. in Matlab, only in inline('...')
• (4) in Matlab, only for anonymous function
• (5) adding an end-of-line
• (6) Smalltalk: postfix operator
• (7) in C++, it is done in place
• (8) in Scheme, not standard, but nearly standard