The are three generators that currently call this method:
A -> B
(1) go -> java
(2) go -> objective-c
(3) go -> go
As discussed below, we only substitute for invalid unicode characters
in case (1).
**Case 1**
Go:
From golang.org/ref/spec:
Identifiers name program entities such as variables and types.
An identifier is a sequence of one or more letters and digits(unicode_digit).
The first character in an identifier must be a letter(unicode_letter | "_" ).
Java:
From https://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.8
`The "Java letters" include uppercase and lowercase ASCII Latin letters
A-Z (\u0041-\u005a), and a-z (\u0061-\u007a), and, for historical reasons,
the ASCII underscore (_, or \u005f) and dollar sign ($, or \u0024). The $
character should be used only in mechanically generated source code or,
rarely, to access pre-existing names on legacy systems.`
Therefore, Go's identifiers are checked in case they break these Java rules.
**Case 2**
There is no objective-c standard specification for valid identifiers.
From some testing it seems that Go and objective-c have identical
valid identifier rules.
**Case 3**
Requires no checking.
Change-Id: I881810eb9355af6a418727ace32cb6ce4266b2a0
Reviewed-on: https://go-review.googlesource.com/14044
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
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