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.

• Various

  { ... }	block (grouping statements, especially when statements are not expressions)
  (* ... *)(1)	block (grouping statements, especially when statements are not expressions)
  //	commenting (until end of line)
  = ~= neqv(1)	equality / inequality (shallow)
  ( ... )	grouping expressions
  valof	use a block as a return value (when statements are not expressions)
  :=	variable assignment or declaration (assignment)
  :	variable assignment or declaration (assignment)
  let v = e(2)	variable assignment or declaration (declaration)

• Functions

  f(a,b,...f) or f[a,b,...] depending on the version	function call
  f(para1, para2, ...) = valof $( ... $)	function definition
  let f(para1, para2, ...) be $( ... $)	function definition (procedures)
  return(3)	function return value (breaks the control flow)
  resultis(4)	function return value (breaks the control flow)

• Control Flow

  / break	breaking control flow (continue / break)
  goto	breaking control flow (goto (unconditional jump))
  return(3)	breaking control flow (returning a value)
  resultis(4)	breaking control flow (returning a value)
  if c do ...	if_then
  test c then b1 or b2	if_then_else
  c -> b1, b2	if_then_else
  ... repeatuntil c	loop (do something until condition)
  while c do ...	loop (while condition do something)
  switchon val case v1: ... case v2: ... default: ...	multiple selection (switch)

• Strings

  "*n"	strings (end-of-line (without writing the real CR or LF character))

• Booleans

  false	false value
  ~	logical not
  \/ / /\(1)	logical or / and (non short circuit (always evaluates both arguments))
  | / &	logical or / and (short circuit)
  true	true value

• Bags and Lists

  a*[i] or a!i or a*(i) depending on the version

  list/array indexing

• Various Data Types

  lv	reference (pointer) (creation)
  rv	reference (pointer) (dereference)

• Mathematics

  rem	modulo (modulo of -3 / 2 is -1)
  -	negation

Remarks

• (1) ascii representation, original uses a special charset
• (2) F#: with indentation
• (3) in Lua, "return xxx" can only appear before a block end. in Matlab, only in inline('...')
• (4) "return" is used when there is no value to return