In a StringTemplate how to temporarily suppress automatic indentation? - stringtemplate-4

Question

In a StringTemplate how to temporarily suppress automatic indentation?
Suppose a template:
fooTemplate() ::= <<
I want this to be indented normally.
# I do not want this line to be indented.
>>
So you can understand the motivation.
I am generating C-lang code and I do not want the preprocessor instructions to be indented. e.g.
#if
To be clear the fooTemplate is not the only template.
It is called by other templates (which may nest several levels deep).
Introducing a special character into the template to temporarily disable indentation would be acceptable.
fooTemplate() ::= <<
I want this to be indented normally.
<\u0008># I do not want this line to be indented.
>>

Answer 1

I see that indentation is actually applied by the 'AutoIndentWriter' https://github.com/antlr/stringtemplate4/blob/master/doc/indent.md
I implemented my own 'SemiAutoIndentWriter' which looks for a magic character (\b in my case) in the stream.
When seen the magic character sets a 'suppressIndent' switch which causes indentation to be suppressed.
package org.stringtemplate.v4;
import java.io.IOException;
import java.io.Writer;
/** Just pass through the text. */
public class SemiAutoIndentWriter extends AutoIndentWriter {
public boolean suppressIndent = false;
public SemiAutoIndentWriter (Writer out) {
super(out);
}
#Override
public int write(String str) throws IOException {
int n = 0;
int nll = newline.length();
int sl = str.length();
for (int i=0; i<sl; i++) {
char c = str.charAt(i);
if ( c=='\b' ) {
suppressIndent = true;
continue;
}
// found \n or \r\n newline?
if ( c=='\r' ) continue;
if ( c=='\n' ) {
suppressIndent = false
atStartOfLine = true;
charPosition = -nll; // set so the write below sets to 0
out.write(newline);
n += nll;
charIndex += nll;
charPosition += n; // wrote n more char
continue;
}
// normal character
// check to see if we are at the start of a line; need indent if so
if ( atStartOfLine ) {
if (! suppressIndent) n+=indent();
atStartOfLine = false;
}
n++;
out.write(c);
charPosition++;
charIndex++;
}
return n;
}
Note that the '<\b>' is not a recognized special character by ST4 but '' is recognized.