firDiagnostic as KtPsiDiagnostic,
            token,
        )
    }
    add(FirErrors.UNDERSCORE_IS_RESERVED) { firDiagnostic ->
        UnderscoreIsReservedImpl(
            firDiagnostic as KtPsiDiagnostic,
            token,
        )
    }
    add(FirErrors.UNDERSCORE_USAGE_WITHOUT_BACKTICKS) { firDiagnostic ->
        UnderscoreUsageWithoutBackticksImpl(

		// A is 65, a is 97
		if v >= 'a' {
			b.WriteRune(v)
			continue
		}
		// v is capital letter here
		// disregard first letter
		// add underscore if last letter is capital letter
		// add underscore when previous letter is lowercase
		// add underscore when next letter is lowercase
		if (i != 0 || i == l-1) && ((i > 0 && rune(camel[i-1]) >= 'a') ||
			(i < l-1 && rune(camel[i+1]) >= 'a')) {
			b.WriteRune('_')

and <code>A</code> through <code>F</code> represent values 10 through 15.
</p>

<p>
For readability, an underscore character <code>_</code> may appear after
a base prefix or between successive digits; such underscores do not change
the literal's value.
</p>
<pre class="ebnf">
int_lit        = decimal_lit | binary_lit | octal_lit | hex_lit .

  for (int i = 0; i < ninputs; ++i) body_outputs[i] = {nullptr, -1};
  const char* name = nullptr;

  for (int i = 0; i < ninputs; ++i) {
    // TODO(skyewm): prefix names with underscore (requires some plumbing)
    if (!CreateInput(inputs[i], cond_graph, StrCat("cond_input", i).c_str(),
                     &cond_inputs[i], status)) {
      break;
    }

* Allow Secret & ConfigMap keys to contain caps, dots, and underscores ([#25458](https://github.com/kubernetes/kubernetes/pull/25458), [@errm](https://github.com/errm))