A Python 3 library with convenience functions for generating code in any language.
Based on the code generation backend in Stone that's used to generate code in many languages: C#, Java, Python, Ruby, Rust, Typescript, and more.
You know all of the pains with code generation (coding, build process, maintenance), but have decided you have no other choice. This library makes generating code a little bit more manageable.
If your code generation needs are simple, consider using a template language such as Jinja2.
pip3 install code-writer
You'll need to import CodeWriter
:
from code_writer import CodeWriter
You probably want to write the output of render()
to a file, but for
illustrative purposes we'll print them.
cw = CodeWriter()
cw.emit('hello,')
with cw.indent():
cw.emit('world.')
print(cw.render())
Output:
hello,
world.
cw = CodeWriter()
cw.emit('if True:')
with cw.indent():
cw.emit('print("hello, world.")')
print(cw.render())
Output:
if True:
print("hello, world.")
Use block()
to create an indented block enclosed by curly braces.
cw = CodeWriter()
with cw.block(before='if true', delim=('{', '}')):
cw.emit('println!("hello, world.");')
print(cw.render())
Output:
if true {
println!("hello, world.");
}
You can also set a default delimiter:
cw = CodeWriter(default_delim=('{', '}'))
cw = CodeWriter(use_tabs=True)
cw = CodeWriter(default_dent=2)
cw = CodeWriter()
cw.emit_list([], ('[', ']'), before='let li1 = ', after=';')
cw.emit_list(['1'], ('[', ']'), before='let li2 = ', after=';')
cw.emit_list(['1', '2', '3'], ('[', ']'), before='let li3 = ', after=';')
cw.emit_list(['1', '2', '3'], ('[', ']'), before='let li4 = ', after=';', compact=True)
print(cw.render())
Output:
let li1 = [];
let li2 = [1];
let li3 = [
1,
2,
3,
];
let li4 = [1,
2,
3];
This is useful for documentation.
# Artificially set col width low to show wrapped text
cw = CodeWriter(default_width=25)
cw.emit('/**')
cw.emit_wrapped_text(
'@param param1 an explanation of what this argument does.',
prefix=' * ',
indent_after_first=True,
)
cw.emit('*/')
print(cw.render())
Output:
/**
* @param param1 an
* explanation of
* what this argument
* does.
*/
preamble = """\
This
is
a
preamble.
"""
cw = CodeWriter()
cw.emit_raw(preamble)
print(cw.render())
Output:
This
is
a
preamble.
Sometimes you'll want a newline after every iteration of logic, but not for the last iteration.
cw = CodeWriter()
with cw.block(before='if true', delim=('{', '}')):
for i in range(3):
cw.emit('println!("{}");'.format(i))
cw.emit()
print(cw.render())
Output:
if true {
println!("0");
println!("1");
println!("2");
}
The gap after the last println!()
is undesirable. To fix, do this:
cw = CodeWriter()
with cw.block(before='if true', delim=('{', '}')):
for i in range(3):
cw.emit('println!("{}");'.format(i))
cw.emit()
cw.trim_last_line_if_empty()
print(cw.render())
Output:
if true {
println!("0");
println!("1");
println!("2");
}
Depending on your target language, you may need to output names that are PascalCase, camelCase, underscore_delimited, or dash-delimited.
from code_writer import fmt_camel, fmt_dashes, fmt_pascal, fmt_underscores
# The input name can be a mix of formatting. These helpers will aggressively
# split the word and re-assemble as desired.
text = 'a-B-HiHo-merryOh_yes_no_XYZ'
assert fmt_camel(text) == 'aBHiHoMerryOhYesNoXyz'
assert fmt_dashes(text) == 'a-b-hi-ho-merry-oh-yes-no-xyz'
assert fmt_pascal(text) == 'ABHiHoMerryOhYesNoXyz'
assert fmt_underscores(text) == 'a_b_hi_ho_merry_oh_yes_no_xyz'