This page summarizes the lexical syntax for Format specifiers.

String Value Format

StringFormat := IntegerLiteral | {EqualSpace  StringBody*  StringTail}
StringBody   := {Character | Separator}  Repeat
StringTail   := [Character '#']  EqualSpace
Separator    := '_' | '.' | ',' | '-' | '/'

EqualSpace   := {('='  Printable  Repeat)* | (' '  Repeat)}*
Character    := 'L' | 'U' | 'C' | 'X' | 'l' | 'u' | 'c' | 'x'
Repeat       := ['1' to '9'  ['0' to '9']]
Printable    := ' ' to '~'

Decimal Integer Value Format

IntegerFormat := EqualSpace  {DecimalNumber | Character}  EqualSpace
Character     := 'L' | 'U' | 'C' | 'l' | 'u' | 'c'

DecimalNumber := Mantissa  ['#']  [Fraction]

Mantissa      := Sign  ['$']  {ZeroNull  [DecimalComma]} | DecimalComma
Sign          := ['M' | 'm' | 'S' | 's']
ZeroNull      := (Zero  ({'_'* | ','}  Zero)*) | (Null ({'_'* | ','}  Null)*)
DecimalComma  := Decimal  ({'_'* | ','}  Decimal)*
Fraction      := '.'  ZeroUnder  {Zero | DecimalUnder | (NullUnder  Null)}

DecimalUnder  := (Decimal  '_'*)*  Decimal
ZeroUnder     :=    (Zero  '_'*)*
NullUnder     :=    (Null  '_'*)*

Decimal       := {'D' | 'd'}  Repeat
Zero          := {'Z' | 'z'}  Repeat
Null          := {'N' | 'n'}  Repeat

Bitwise Integer Value Format

BitwiseNumber := EqualSpace  ['#']  {ZeroUnder | NullUnder}  BitwiseRadiax  EqualSpace
BitwiseRadix  := {HexRadix | OctalRadix | BinaryRadix}  ['#']

HexRadix      := Hex     ('_'*  Hex)*
OctalRadix    := Octal   ('_'*  Octal)*
BinaryRadix   := Binary  ('_'*  Binary)*

Hex           := {'H' | 'h'}  Repeat
Binary        := {'B' | 'b'}  Repeat
Octal         := {'O' | 'o'}  Repeat

Decimal Real Value Format

RealFormat := EqualSpace  DecimalNumber  EqualSpace

Scientific Decimal Real Value Format

SciFormat     := EqualSpace  SciMantissa  Fraction  Exponent  EqualSpace
SciMantissa   := Sign  NullUnder  DecimalUnder
Exponent      := {'E' | 'e'}  Sign  {'N' | 'n'}*  {'D' | 'd'}*  ['#']

Scientific Hexadecimal Real Value Format

HexSciFormat := EqualSpace  Sign  HexReal  HexExponent  EqualSpace
HexReal      := ['#']  '1.'  HexRadix    ['#']
HexExponent  := {'P' | 'p'}  Sign  Hex+  ['#']