▼Unlib: Helpful Utilities from Untyped
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symbol+ false?
gensym/ interned
symbol-append
symbol-length
symbol-upcase
symbol-downcase
number->symbol
symbol->number
number+ false->symbol+ false
symbol+ false->number+ false
string+ false->symbol+ false
symbol+ false->string+ false
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27 Symbol utilities

 (require (planet untyped/unlib/symbol))
Useful symbol utilities.

(symbol+false? item) → boolean?
  item : any
Returns #t if item is a symbol or #scheme[#f].

(gensym/interned [base]) → symbol?
  base : (U symbol? string?) = "g"
Like gensym but returns an interned symbol that can be compared with other symbols using eq?.

Examples:

  > (define sym1 (gensym))
  > sym1

  g255

  > (eq? sym1 (string->symbol (symbol->string sym1)))

  #f

  > (define sym2 (gensym/interned))
  > sym2

  g256

  > (eq? sym2 (string->symbol (symbol->string sym2)))

  #t

(symbol-append sym ...) → symbol?
  sym : symbol?
The symbol equivalent of string-append. Returns an interned symbol.

Examples:

  > (symbol-append 'abc 'def 'ghi)

  abcdefghi

  > (symbol-append 'abc)

  abc

  > (symbol-append)

  ||

(symbol-length sym) → natural?
  sym : symbol?
The symbol equivalent of string-length.

Example:

  > (symbol-length 'AbC123)

  6

(symbol-upcase sym) → symbol?
  sym : symbol?
The symbol equivalent of string-upcase. Returns an interned symbol.

Example:

  > (symbol-upcase 'AbC123)

  ABC123

(symbol-downcase sym) → symbol?
  sym : symbol?
The symbol equivalent of string-downcase. Returns an interned symbol.

Example:

  > (symbol-downcase 'AbC123)

  abc123

(number->symbol num) → symbol?
  num : number?
The symbol equivalent of number->string. Returns an interned symbol.

Examples:

  > (number->symbol 123)

  |123|

  > (number->symbol (/ 1 3))

  |1/3|

(symbol->number sym) → number?
  sym : symbol?
The symbol equivalent of string->number. Returns #f if sym has no numeric equivalent.

Examples:

  > (symbol->number '|123|)

  123

  > (symbol->number 'abc)

  #f

(number+false->symbol+false num) → (U symbol? #f)
  num : (U number? #f)
A version of number->symbol that accepts and passes through #f.

(symbol+false->number+false sym) → (U number? #f)
  sym : (U symbol? #f)
A version of symbol->number that accepts and passes through #f.

(string+false->symbol+false str) → (U symbol? #f)
  str : (U string? #f)
A version of string->symbol that accepts and passes through #f.

(symbol+false->string+false sym) → (U string? #f)
  sym : (U symbol? #f)
A version of symbol->string that accepts and passes through #f.

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