Control Flow

• sequence

  ,	C, C++, Go, JavaScript, Matlab, Perl, Pike, Prolog, Scilab
  .	Smalltalk
  ;	Ada, Awk, B, Beta, BourneShell, C, C#, C++, E, F#, FishShell, GNU-sed, Go, Haskell, Io, Java, JavaScript, Maple, Mathematica, Matlab, merd, Modula-3, OCaml, Pascal, Perl, Perl6, PHP, Pike, PL/I, Pliant, Python, Ruby, SML, Tcl, YCP
  :	Maple
  nothing, optionally ;	Classic REXX, Lua
  space	Eiffel, Rebol
  end-of-line	Assembler, Awk, Basic, BourneShell, CoffeeScript, E, F#, FishShell, Fortran, GNU-sed, Haskell, Io, JavaScript, Lua, Matlab, merd, Pliant, Python, Ruby, Tcl
  (begin ...)	Scheme
  (progn ...) (prog1 ...) (prog2 ...)	Common Lisp, Emacs Lisp
  >>	Haskell

• if_then

  if c then ...	CoffeeScript, F#, merd, OCaml, Pascal, Tcl
  if c then ... end	Eiffel, Lua, Oz, Ruby
  if c then ... end if	Ada, Maple
  if c then ... fi	Maple
  if c; then ... fi	BourneShell
  if (c) then ... end	Dylan
  if c do ...	BCPL
  IF c THEN ... END	Modula-2, Modula-3
  if (c) ...	Awk, B, C, C#, C++, Java, JavaScript, PHP, Pike, YCP
  if c: ...	Python
  if c ...	Pliant, Rebol, Tcl
  if (c): ... endif	PHP
  if c {...}	Go, Perl6
  if c [...]	Logo
  if (c) {...}	E, Perl, Yorick
  IF c ...	MUMPS
  c -> ...	FL
  c ... if	PostScript
  ... if c	Perl, Ruby
  c if b1 then	Forth
  (if c ...)	Common Lisp, Scheme
  (when c ...)	Emacs Lisp
  c and ...	Perl, Ruby
  if(c, ...)	Io
  If[c, ...]	Mathematica
  if(c) then(...)	Io
  c ifTrue(...)	Io
  c ifTrue: ...	Smalltalk
  <xsl:if test="c">...</xsl:if>	XSLT
  if c ... endif	Vimscript
  If c Then ...	Visual Basic
  If c ... End If	Visual Basic
  if c; ... end	Ruby
  if c; ...; end	FishShell
  if c, ..., end	Matlab
  if c ... end	Matlab, Ruby
  if c then ; ... if c then ... if c then do ... end	Classic REXX
  c and ...	Perl
  t label	GNU-sed
  if c ...	CoffeeScript

• if_then_else

  if c then b1 else b2	CoffeeScript, F#, Haskell, merd, OCaml, SML
  if c then b1 else b2 end	Eiffel, Lua, Ruby
  if c then b1 elsif c2 then b2 else b3 end if	Ada
  if c then b1 elseif c2 then b2 else b3 end	Eiffel, Oz
  if (c) then b1 elseif (c2) then b2 else b3 end	Dylan
  IF c THEN b1 ELSIF c2 THEN b2 ELSE b3 END	Modula-3
  If c Then b1 ElseIf c2 Then b2 Else b3 End If	Modula-2
  if (c) b1 else b2	Awk, B, C, C#, C++, Java, JavaScript, Pike, YCP
  if c b1 elsif c2 b2 b3	Tcl
  if c then b1 elseif c2 then b2 else b3	Tcl
  if c then begin b1 end else begin b2 end	Pascal
  if c b1 eif c2 b2 else b3	Pliant
  if c then b1 elif c2 then b2 else b3 end if	Maple
  if c; then b1; elif c2; then b2; else b3; fi	BourneShell
  if c; b1; else b2; end	FishShell
  if c1, b1, elseif c2, b2, else, b3, end	Matlab
  if (c) b1 elseif (c2) b2 else b3	PHP
  if (c): b1 elseif (c2): b2 else: b3 endif	PHP
  if (c) {b1} elsif (c2) {b2} else {b3}	Perl
  if (c) {b1} else {b2}	E, Yorick
  (if c b1 b2)	Common Lisp, Scheme
  (if c then b1 else b2)	Mercury
  (c -> b1 ; c2 -> b2 ; b3)	Mercury
  c -> b1 ; b2	FL
  if(c, b1, b2)	Io
  If[c, b1, b2]	Mathematica
  if(c) then(b1) else(b2)	Io
  c ifTrue: b1 ifFalse: b2	Smalltalk
  ifelse c [b1] [b2]	Logo
  shunt c b1 c2 b2 b3	Pliant
  either c b1 b2 / if/else c b1 b2	Rebol
  (cond (c b1) (c2 b2) (t b3))	Common Lisp, Emacs Lisp
  (cond (c b1) (c2 b2) (else b3))	Scheme
  Which[c, b1, c2, b2, True, b3]	Mathematica
  c -> b1 ; c2 -> b2 ; b3	Prolog
  case when c; b1 when c2; b2 else b3 end	Ruby
  test c then b1 or b2	BCPL
  e | c = b1 | c2 = b2 | otherwise = b3(1)	Haskell
  c b1 b2 ifelse	PostScript
  c if b1 else b2 then	Forth
  c ? b1 : b2	Awk, B, C, C#, C++, Java, JavaScript, Perl, PHP, Ruby, Tcl, YCP, Yorick
  c ?? b1 !! b2	Perl6
  b1 if c else b2(2)	Python
  $SELECT(c:b1,c2:b2,1:b3)	MUMPS
  c -> b1, b2	BCPL
  (if c then b1 else b2 fi)	Beta
  <xsl:choose> <xsl:when test="c"> b1 </xsl:when> <xsl:when test="c2"> b2 </xsl:when> <xsl:otherwise> b3 </xsl:otherwise> </xsl:choose>	XSLT
  if c1 ... elseif c2 ... else ... endif	Vimscript
  If c Then b1 Else b2	Visual Basic
  If c b1 Else b2 End If	Visual Basic
  if c: b1 elif c2: b2 else: b3	Python
  if c b1 elsif c2 b2 else b3 end	Ruby
  if c b1 elseif c2 b2 else b3 end	Matlab
  if c then ; b1 ; else ; b2 if c then b1 else b2 if c then do b1 ... end else do b2 ... end	Classic REXX
  IF c ... ELSE ...	MUMPS
  if c b1 else if c2 b2 else b3	CoffeeScript
  if c {b1} else if c2 {b2} else {b3}	Go

• ifnot_then (unless)

  unless	CoffeeScript, Emacs Lisp, Perl
  ifFalse	Smalltalk
  if(c) not then(...)	Io

• multiple selection (switch)

  switch (val) { case v1: ...; break; case v2: case v3: ...; break; default: ...; }	C, C++, Java, JavaScript, PHP, Pike
  switch val { case v1: ...; goto done; case v2: case v3: ...; goto done; } ...; done:	B
  switch (val) { case v1: ...; break; case v2: case v3: ...; break; default: ...; break; } (3)	C#
  switch (val) { match v1 { ... } match v2 { ... } match _ { ... } }	E
  switchon val case v1: ... case v2: ... default: ...	BCPL
  switch val case v1 ... case v2 v3 ... case '*' ... end	FishShell
  switch val case v1 ... case {v2,v3} ... otherwise ... end	Matlab
  case val of v1 : ...; v2, v3 : ... else ... end	Pascal
  switch val { v1 {...} v2 - v3 {...} default {...} }	Tcl
  case val in v1) statement1 ;; v2|v3) statement23 ;; *) statement_else ;; esac	BourneShell
  (if val // v1 then ... // v2 then ... else ... if)	Beta
  match val with | v1 -> ... | v2 | v3 -> ... | _ -> ...	F#, OCaml
  case val of v1 => ... | v2 => ... | _ => ...	SML
  CASE val OF v1 => ... | v2 => ... ELSE => ... END	Modula-3
  case val of v1 -> ... v2 -> ... _ -> ...	Haskell
  val case v1 of ... endof v2 of ... endof ... endcase	Forth
  val. v1 -> ... v2 -> ... _ -> ...	merd
  (case val ((v1) ...) ((v2) ...) (otherwise ...))	Common Lisp
  (case val ((v1) ...) ((v2) ...) (else ...))	Scheme
  case val is when v1 => ... when v2 | v3 => ... when others => ... end case;	Ada
  case val when v1; ... when v2, v3; ... else ... end	Ruby
  inspect val when v1 then statement1 when v2, v3 => statement23 else statement_else end	Eiffel
  select (val); when (v1) statement1; when (v2, v3) statement23; otherwise statement_else; end;	PL/I
  X = val, (X = v1, ... ; X = v2, ... ; ...)	Mercury, Prolog
  my %case = ( v1 => sub { ... }, v2 => sub { ... }, ); if ($case{val}) { $case{val}->() } else { ... }	Perl
  use Switch; switch ($val) { case v1 { ... } case v2 { ... } else ... }) (4)	Perl
  given $val { when v1 { ... } when v2 { ... } default { ... } }	Perl6
  Select val Case v1 ... Case v2, v3 ... Case Else ... End Select	Visual Basic
  switch (val) { v1 { ... } v2 { ... } default { ... } }	MSH
  switch val [ v1 [...] v2 [...] ] switch/default [ v1 [...] v2 [...] ][...]	Rebol
  val caseOf: {[v1]->[...]. [v2]->[...]} otherwise: ...	Squeak
  Switch[val, v1, ..., v2, ..., _, ...]	Mathematica
  select when v1 ... when v2 | v3 ... otherwise ... end	Classic REXX
  CASE val WHEN v1 THEN ... WHEN v2 THEN ... ELSE ... END	SQL92
  switch val { case v1, v2, ...: ... fallthrough case v3: ... default: ... }	Go

• loop

  forever loop

  loop	CoffeeScript, merd, Perl6, PostScript, Ruby
  loop(...)	Io
  loop ... end loop	Ada
  LOOP ... END	Modula-3
  (loop do ...)	Common Lisp
  cycle (# do ... #)	Beta
  repeat	Squeak
  begin ... again	Forth
  forever	Logo, Rebol
  Do ... Loop	Visual Basic
  do forever ... end	Classic REXX
  for {}	Go

  while condition do something

  while (c) ...	Awk, B, C, C#, C++, E, Java, JavaScript, Perl, PHP, Pike, Ruby, YCP, Yorick
  while c ...	CoffeeScript, Perl6, Tcl
  while c loop ... end loop	Ada
  while c do ...	BCPL, Pascal, SML
  while c do ... done	F#, OCaml
  while c do ... end do	Maple
  while c do ... end	Lua
  WHILE c DO ... END	Modula-3
  while c: ...	Python
  while c; do ...; done	BourneShell
  while c; ...; end	FishShell
  while c, ..., end	Matlab
  while [c][...]	Rebol
  while c [...]	Logo
  while(c, ...)	Io
  While[c, ...]	Mathematica
  do.while [...] c	Logo
  c whileTrue: ...	Smalltalk
  (loop while c do ...)	Common Lisp
  loop (# while ::< (# do c -> value #) do ... #)	Beta
  begin c while ... repeat	Forth
  from until not c loop ... end	Eiffel
  while c ...	Pliant
  while c do ...	F#
  Do While c ... Loop	Visual Basic
  while c ... endwhile	Vimscript
  do while c ... end	Classic REXX
  for c {...}	Go

  do something until condition

  do ... until c	Perl6
  do {...} until c	Perl
  do ... while (!c)	Awk, C, C#, C++, Java, JavaScript, Pike, Yorick
  begin ... end until c	Ruby
  begin ... c until	Forth
  REPEAT ... UNTIL c	Modula-3
  loop (# until ::< (# do c -> value #) do ... #)	Beta
  loop ... exit when c; end loop	Ada
  (loop do ... until c)	Common Lisp
  ... repeatuntil c	BCPL
  repeat ... until c	Lua, Pascal
  repeat ... until (c)	YCP
  repeat, ..., c	Prolog
  until [... c]	Rebol
  until c [...]	Logo
  do.while [...] c	Logo
  While[...; c]	Mathematica
  [...] whileFalse: [c]	Smalltalk
  Do ... Loop Until c	Visual Basic

  for each value in a numeric range, 1 increment (see also the entries about ranges)

  for (int i = 1; i <= 10; i++) ...	C, C#, C++
  for (i = 1; i <= 10; i++) ...	Awk, JavaScript
  for ($i = 1; $i <= 10; $i++) ...	PHP
  foreach my $i (1 .. 10) { ... }	Perl
  foreach ($i in 1..10) { ... }	MSH
  for (1 .. 10) -> $i { ... }	Perl6
  for i = 1:10, ..., end	Matlab
  for i = 1, 10 do ... end	Lua
  for i := 1 to 10 do ...	Pascal
  for i = 1 to 10 do ... done	F#, OCaml
  For i = 1 To 10 ... Next	Visual Basic
  for i in 1 .. 10 loop ... end loop	Ada
  for i in 1 .. 10 do ... done	F#
  for i in [1..10] ...	CoffeeScript
  for i in xrange(1, 11)	Python
  for i in (seq 10); ...; end	FishShell
  FOR I=1:1:10 ...	MUMPS
  for i from 1 to 10 do ... end do	Maple
  for [i 1 10 +1] [...]	Logo
  for {set i 1} {$i <= 10} {incr i} {...}	Tcl
  1 1 10 ... for	PostScript
  11 1 do ... loop	Forth
  (1..10).each {|i| ... }	Ruby
  1.upto(10) {|i| ... }	Ruby
  1 to(10) foreach(...)	Io
  1 to: 10 do: [...]	Smalltalk
  (loop for i from 1 to 10 do ...)	Common Lisp
  do label i = 1, 10	Fortran
  Do[..., {i, 1, 10}](5)	Mathematica
  do i = 1 for 10 ... end	Classic REXX
  for i := 1; i <= 10; i++ {...}	Go

  for each value in a numeric range, 1 decrement

  for X := 10 downto 1 do ...	Pascal
  for i = 10 downto 1 do ... done	F#, OCaml
  for i in reverse 1 .. 10 loop ... end loop	Ada
  for i in 10 .. -1 .. 1 do ... done	F#
  for (int i = 10; i >= 1; i--) ...	C, C#, C++
  for (my $i = 10; $i >= 1; $i--) { ... }	Perl
  loop (my $i = 10; $i >= 1; $i--) { ... }	Perl6
  for (i = 10; i >= 1; i--) ...	Awk, JavaScript
  for ($i = 10; $i >= 1; $i--) ...	PHP
  from i := 10 until i < 1 loop ... i := i - 1 end	Eiffel
  for i = 10:-1:1, ..., end	Matlab
  for i = 10, 1, -1 do ... end	Lua
  For i = 10 To 1 Step -1 ... Next	Visual Basic
  for i in xrange(10, 0, -1)	Python
  for i in `seq 10 -1 1`; do ...; done	BourneShell
  for i in (seq 10 -1 1); ...; end	FishShell
  for i from 10 to 1 by -1 do ... end do	Maple
  for [i 1 10 -1] [...]	Logo
  FOR I=10:-1:1 ...	MUMPS
  for {set i 10} {$i >= 1} {incr i -1} {...}	Tcl
  10 -1 1 ... for	PostScript
  1 10 do ... -1 +loop	Forth
  1 to: 10 by: -1 do: [...]	Smalltalk
  10 to(1) foreach(...)	Io
  10.downto(1) {|i| ... }	Ruby
  (loop for i from 1 to 10 by -1 do ...)	Common Lisp
  do label i = 10, 1, -1	Fortran
  Do[..., {i, 10, 1, -1}]	Mathematica
  do i = 10 to 1 by -1 ... end	Classic REXX
  for i in [10..1] ...	CoffeeScript
  for i := 10; i >= 1; i-- {...}	Go

  for each value in a numeric range, free increment

  for (int i = 1; i <= 10; i += 2) ...	C, C#, C++, Pike
  for (i = 1; i <= 10; i += 2) ...	Awk, JavaScript
  for ($i = 1; $i <= 10; $i += 2) ...	PHP
  for (my $i = 1; $i <= 10; $i += 2) { ... }	Perl
  loop (my $i = 1; $i <= 10; $i += 2) { ... }	Perl6
  from i := 1 until i > 10 loop ... i := i + 2 end	Eiffel
  for i = 1:3:10, ..., end	Matlab
  for i = 1, 10, 2 do ... end	Lua
  For i = 1 To 10 Step 2 ... Next	Visual Basic
  for i in 1 .. 2 .. 10 do ... done	F#
  for i in xrange(1, 11, 2)	Python
  for i in (seq 1 2 10); ...; end	FishShell
  for i from 1 to 10 by 2 do ... end do	Maple
  for [i 1 10 2] [...]	Logo
  FOR I=1:2:10 ...	MUMPS
  for {set i 0} {$i <= 10} {incr i 2} {...}	Tcl
  1 2 10 ... for	PostScript
  11 1 do ... 2 +loop	Forth
  1 to: 10 by: 2 do: [...]	Smalltalk
  (1..10).step(2) {|i| ... }	Ruby
  1 to (9,2) foreach(...)	Io
  (loop for i from 1 to 10 by 2 do ...)	Common Lisp
  do label i = 1, 10, 2	Fortran
  Do[..., {i, 1, 10, 2}]	Mathematica
  do i = 1 to 10 by 2 ... end	Classic REXX
  for i in [1..10] by 2 ...	CoffeeScript
  for i := 1; i <= 10; i += 2 {...}	Go

  for "a la C" (while + initialisation)

  for	Awk, C, C#, C++, Go, Java, JavaScript, Mathematica, MSH, Perl, PHP, Pike, Tcl, Yorick
  loop	Perl6
  for ((x = 0; x < 10; x++)); do ...; done	BourneShell
  from init_code until c loop ... incr_statement end	Eiffel
  (loop with VAR = INITIAL-VALUE ... while CONDITION finally INCREMENT ...)	Common Lisp

• breaking control flow

  returning a value

  return(6)	Ada, Awk, B, BCPL, BourneShell, C, C#, C++, Classic REXX, CoffeeScript, Common Lisp, E, FishShell, Go, Io, Java, JavaScript, Lua, Maple, Matlab, Perl, Perl6, PHP, Pike, Pliant, Python, Rebol, Ruby, Tcl, Vimscript, YCP, Yorick
  Return	Mathematica, Visual Basic
  RETURN	Modula-3
  resultis(7)	BCPL
  return-from xxx	Common Lisp
  ^	Smalltalk
  Exit Function / Exit Sub	Visual Basic
  exit	Forth
  output	Logo

  goto (unconditional jump)

  goto	Ada, B, Basic, BCPL, C, C#, C++, Cobol, Fortran, Go, Logo, MUMPS, Pascal, Perl, PHP5, Yorick
  Goto	Mathematica
  go throw	Common Lisp
  signal	Classic REXX
  b	GNU-sed
  b, bra, jmp	Assembler

  continue / break

  continue / break	Awk, C, C#, C++, CoffeeScript, E, FishShell, Go, Io, Java, JavaScript, Matlab, PHP, Pike, Python, Tcl, YCP, Yorick
  Continue / Break	Mathematica
  next / last	Perl, Perl6
  next / break(8)	Maple, Ruby
  / break	BCPL, Lua
  / break/return	Rebol
  / exit	Ada, PostScript
  / stop	Logo
  restart / leave	Beta, Pliant
  / Exit Do, Exit For	Visual Basic
  / return-from xxx or return	Common Lisp
  iterate / leave	Classic REXX
  / leave	Forth

  redo / retry

  redo/	Perl, Perl6
  redo / retry	Io, Ruby

• exception

  throwing

  raise	Ada, Eiffel, F#, merd, OCaml, Python, Ruby, Scheme-SRFI34, SML
  RAISE	Modula-3
  raise ... end	Oz
  Exception raise	Io
  throw	C#, C++, CoffeeScript, E, Erlang, Forth, Haskell, Java, JavaScript, Logo, PHP5, Pike, Prolog, Rebol
  Throw	Mathematica
  throw/name	Rebol
  die	Perl, Perl6
  return -code	Tcl
  error	Common Lisp, Dylan, Emacs Lisp, Lua, Lua, Maple, Matlab, Pliant, Yorick
  signal	Common Lisp, Dylan, Smalltalk
  signal predefined_condition_name	Classic REXX
  cerror warn	Common Lisp
  [NSException raise:name ...]	Objective-C
  panic(v)	Go

  catching

  try: a except exn: ...	Python
  try a with exn -> ...	F#, OCaml
  try a catch (exn) ...	C#, C++, Java, JavaScript
  try a ... catch exn ...	CoffeeScript
  try { ... } catch(t $v) { ... }	PHP5
  try a catch exn then ... end	Oz
  try a catch exn: ... end try	Maple
  try(a) ; catch(...)	Io
  try { a CATCH exn { ... } }	Perl6
  TRY a EXCEPT exn => ... END	Modula-3
  a handle exn => ...	SML
  a on: exception_name do: [:exn | ...]	Smalltalk
  ifCurtailed	Smalltalk
  rescue	Eiffel, Ruby
  eval {a}; if ($@) ...	Perl
  exception when exception_name =>	Ada
  catch a (\exn -> ...)	Haskell
  catch	Erlang, Forth, Logo, Prolog, Rebol, Tcl
  Catch	Mathematica
  catch/name	Rebol
  catch(...) or catch { ... };	Pike
  if (catch(exn)) { ... } a	Yorick
  pcall	Lua
  with-exception-handler or guard	Scheme-SRFI34
  block a exception(exn) ... end	Dylan
  ?, shy, safe	Pliant
  handler-bind handler-case ignore-errors	Common Lisp
  NS_DURING a NS_HANDLER ... NS_ENDHANDLER	Objective-C
  try a catch ... end	Matlab
  signal on predefined_condition_name ... predefined_condition_name : ...	Classic REXX
  recover()	Go

  cleanup: code executed before leaving

  ensure	Ruby, Smalltalk
  finally	C#, F#, Java, Maple, Python
  FINALLY	Modula-3
  unwind-protect	Common Lisp, Emacs Lisp
  cleanup	Dylan
  dynamic-wind	Scheme

  retrying: after catching an exception, tell the snippet to be re-run

  retry	Eiffel, Ruby, Smalltalk
  restart	Dylan

  resume execution where the exception took place

  resume

  Smalltalk

• call-with-current-continuation

  call-with-current-continuation(9)	Scheme
  callcc	Ruby, SML-NJ

Remarks

• (1) the result goes to "e"
• (2) Python >= 2.5
• (3) "break"s are mandatory, even for "default"!
• (4) Perl >= 5.8.0
• (5) 1 is optional in this example, since min is 1 by default
• (6) in Lua, "return xxx" can only appear before a block end. in Matlab, only in inline('...')
• (7) "return" is used when there is no value to return
• (8) in Ruby, see also catch/throw
• (9) often provided in the abbreviated form call/cc