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Extract branch rewrite function
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@RReverser
RReverser committed Jan 30, 2018
1 parent e718546 commit a221757
Showing 1 changed file with 95 additions and 95 deletions.
190 changes: 95 additions & 95 deletions src/macros.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -310,115 +310,27 @@ pub fn rewrite_macro_def(

let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;

let mac_indent = if multi_branch_style {
indent.block_indent(context.config)
let arm_shape = if multi_branch_style {
shape
.block_indent(context.config.tab_spaces())
.with_max_width(context.config)
} else {
indent
shape
};

let mac_indent_str = mac_indent.to_string(context.config);

let branch_items = itemize_list(
context.codemap,
parsed_def.branches.iter(),
"}",
";",
|branch| branch.span.lo(),
|branch| branch.span.hi(),
|branch| {
// Only attempt to format function-like macros.
if branch.args_paren_kind != DelimToken::Paren {
// FIXME(#1539): implement for non-sugared macros.
return None;
}

let mut result = format_macro_args(branch.args.clone())?;

if multi_branch_style {
result += " =>";
}

// The macro body is the most interesting part. It might end up as various
// AST nodes, but also has special variables (e.g, `$foo`) which can't be
// parsed as regular Rust code (and note that these can be escaped using
// `$$`). We'll try and format like an AST node, but we'll substitute
// variables for new names with the same length first.

let old_body = context.snippet(branch.body).trim();
let (body_str, substs) = replace_names(old_body);

let mut config = context.config.clone();
config.set().hide_parse_errors(true);

result += " {";

let has_block_body = old_body.starts_with('{');

let body_indent = if has_block_body {
mac_indent
} else {
// We'll hack the indent below, take this into account when formatting,
let body_indent = mac_indent.block_indent(&config);
let new_width = config.max_width() - body_indent.width();
config.set().max_width(new_width);
body_indent
};

// First try to format as items, then as statements.
let new_body = match ::format_snippet(&body_str, &config) {
Some(new_body) => new_body,
None => match ::format_code_block(&body_str, &config) {
Some(new_body) => new_body,
None => return None,
},
};

// Indent the body since it is in a block.
let indent_str = body_indent.to_string(&config);
let mut new_body = new_body
.trim_right()
.lines()
.fold(String::new(), |mut s, l| {
if !l.is_empty() {
s += &indent_str;
}
s + l + "\n"
});

// Undo our replacement of macro variables.
// FIXME: this could be *much* more efficient.
for (old, new) in &substs {
if old_body.find(new).is_some() {
debug!(
"rewrite_macro_def: bailing matching variable: `{}` in `{}`",
new, ident
);
return None;
}
new_body = new_body.replace(new, old);
}

if has_block_body {
result += new_body.trim();
} else if !new_body.is_empty() {
result += "\n";
result += &new_body;
result += &mac_indent_str;
}

result += "}";

Some(result)
},
|branch| branch.rewrite(context, arm_shape, multi_branch_style),
context.codemap.span_after(span, "{"),
span.hi(),
false,
).collect::<Vec<_>>();

let arm_shape = shape
.block_indent(context.config.tab_spaces())
.with_max_width(context.config);

let fmt = ListFormatting {
tactic: DefinitiveListTactic::Vertical,
separator: if def.legacy { ";" } else { "" },
Expand All @@ -432,7 +344,7 @@ pub fn rewrite_macro_def(

if multi_branch_style {
result += " {\n";
result += &mac_indent_str;
result += &arm_shape.indent.to_string(context.config);
}

result += write_list(&branch_items, &fmt)?.as_str();
Expand Down Expand Up @@ -827,6 +739,94 @@ struct MacroBranch {
body: Span,
}

impl MacroBranch {
fn rewrite(&self, context: &RewriteContext, shape: Shape, multi_branch_style: bool) -> Option<String> {
// Only attempt to format function-like macros.
if self.args_paren_kind != DelimToken::Paren {
// FIXME(#1539): implement for non-sugared macros.
return None;
}

let mut result = format_macro_args(self.args.clone())?;

if multi_branch_style {
result += " =>";
}

// The macro body is the most interesting part. It might end up as various
// AST nodes, but also has special variables (e.g, `$foo`) which can't be
// parsed as regular Rust code (and note that these can be escaped using
// `$$`). We'll try and format like an AST node, but we'll substitute
// variables for new names with the same length first.

let old_body = context.snippet(self.body).trim();
let (body_str, substs) = replace_names(old_body);

let mut config = context.config.clone();
config.set().hide_parse_errors(true);

result += " {";

let has_block_body = old_body.starts_with('{');

let body_indent = if has_block_body {
shape.indent
} else {
// We'll hack the indent below, take this into account when formatting,
let body_indent = shape.indent.block_indent(&config);
let new_width = config.max_width() - body_indent.width();
config.set().max_width(new_width);
body_indent
};

// First try to format as items, then as statements.
let new_body = match ::format_snippet(&body_str, &config) {
Some(new_body) => new_body,
None => match ::format_code_block(&body_str, &config) {
Some(new_body) => new_body,
None => return None,
},
};

// Indent the body since it is in a block.
let indent_str = body_indent.to_string(&config);
let mut new_body = new_body
.trim_right()
.lines()
.fold(String::new(), |mut s, l| {
if !l.is_empty() {
s += &indent_str;
}
s + l + "\n"
});

// Undo our replacement of macro variables.
// FIXME: this could be *much* more efficient.
for (old, new) in &substs {
if old_body.find(new).is_some() {
debug!(
"rewrite_macro_def: bailing matching variable: `{}`",
new
);
return None;
}
new_body = new_body.replace(new, old);
}

if has_block_body {
result += new_body.trim();
} else if !new_body.is_empty() {
result += "\n";
result += &new_body;
result += &shape.indent.to_string(&config);
}

result += "}";

Some(result)
}
}

#[cfg(test)]
mod test {
use super::*;
Expand Down

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