Question

How do I indent a multiline string in the context of string formatting? e.g.

'''
<
     %s
>
''' % (paragraph)

where paragraph contains newlines. (‘foo\nbar’)

If I use the above code, I get output like this:

'''
<
    foo
bar
>
'''

when I really want this:

'''
<
    foo
    bar
>
'''

I know I could do something like:

'''
<
%s
>
''' % (paragraph)

but this breaks readability for my purposes.

I also realize I could just write some code to indent all but the first line by 1 indent, but this isn’t really an extensible solution (what if I have 2 indents? or 3? etc.)

EDIT:
Before you post an answer, consider how your solution works with something like this:

'''
<
    %s
    <
        %s
        %s
        <
            %s
        >
    >
>
''' % (p1, p2, p3, p4)

Answer 1

Okay, the simple doesn’t suit your purposes. Either you need to use a document object model and a flattening system with appropriate indentation.

Or, you could do something fairly hacky to detect the amount of whitespace before each substitution. This is pretty fragile:

import re

def ind_sbt(text,indent='\t'):
    return text.replace('\n','\n%s' % (indent,))

def adjust_indents(fmtstr,*args):
    """Hacky, crude detection of identation level"""
    indented_substitutions = re.compile(r'\n(\s+)%s')
    return fmtstr % tuple([ ind_sbt(arg,indent=i) for (arg,i) in zip(args,indented_substitutions.findall(fmtstr))])

p1 = p2 = p3 = p4 = "foo\nbar"

print adjust_indents('''
<
    %s
    <
        %s
        %s
        <
            %s
        >
    >
>
''',p1,p2,p3,p4)

Yielding:

<
        foo
        bar
        <
                foo
                bar
                foo
                bar
                <
                        foo
                        bar
                >
        >
>