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Source for ticket #80

cc

changetime

2010-11-15 09:53:25

component

WG1 - Reader Syntax

description

In R5RS, a token that begins with a numeric character (`0-9, +, -`) but is not a number is considered erroneous, with the exceptions of the symbols `+` and `-`.  R6RS extends this to tokens that begin with `->`.

Shall we simply say that any such token is a valid symbol?  Currently, Racket, Gauche, MIT Scheme, Gambit, Chicken, Scheme48/scsh, Guile, Kawa and SISC do so.  Of these, Gauche, Kawa, and SISC output such identifiers with `|` escaping, showing that these implementations treat such symbols as second-class (or perhaps for increased portability of Scheme data).  Chibi accepts symbols with no digits such as `-foo`, but reject tokens like `2a2`.

Common Lisp reserves such tokens under the name of "potential numbers", but as far as I can tell nobody uses them for anything -- it's too difficult to mutate the readtable, and there is no standard hook to provide an interpretation.

id

keywords

milestone

owner

alexshinn

priority

major

reporter

cowan

resolution

duplicate

severity

status

closed

summary

Extended symbol/identifier syntax

time

2010-09-07 17:46:22

type

defect

Changes

Change at time 2010-11-15 09:53:25

author

alexshinn

field

comment

newvalue

Duplicate of #12.

oldvalue

raw-time

1289786005000000

ticket

time

2010-11-15 09:53:25

Change at time 2010-11-15 09:53:25

author

alexshinn

field

resolution

newvalue

duplicate

oldvalue

raw-time

1289786005000000

ticket

time

2010-11-15 09:53:25

Change at time 2010-11-15 09:53:25

author

alexshinn

field

status

newvalue

closed

oldvalue

new

raw-time

1289786005000000

ticket

time

2010-11-15 09:53:25