68 lines
1.8 KiB
Rust
68 lines
1.8 KiB
Rust
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use quote::{Tokens, ToTokens};
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pub enum Fragment {
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/// Tokens that can be used as an expression.
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Expr(Tokens),
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/// Tokens that can be used inside a block. The surrounding curly braces are
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/// not part of these tokens.
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Block(Tokens),
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}
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macro_rules! quote_expr {
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($($tt:tt)*) => {
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$crate::fragment::Fragment::Expr(quote!($($tt)*))
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}
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}
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macro_rules! quote_block {
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($($tt:tt)*) => {
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$crate::fragment::Fragment::Block(quote!($($tt)*))
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}
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}
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/// Interpolate a fragment in place of an expression. This involves surrounding
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/// Block fragments in curly braces.
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pub struct Expr(pub Fragment);
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impl ToTokens for Expr {
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fn to_tokens(&self, out: &mut Tokens) {
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match self.0 {
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Fragment::Expr(ref expr) => expr.to_tokens(out),
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Fragment::Block(ref block) => {
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out.append("{");
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block.to_tokens(out);
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out.append("}");
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}
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}
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}
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}
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/// Interpolate a fragment as the statements of a block.
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pub struct Stmts(pub Fragment);
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impl ToTokens for Stmts {
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fn to_tokens(&self, out: &mut Tokens) {
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match self.0 {
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Fragment::Expr(ref expr) => expr.to_tokens(out),
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Fragment::Block(ref block) => block.to_tokens(out),
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}
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}
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}
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/// Interpolate a fragment as the value part of a `match` expression. This
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/// involves putting a comma after expressions and curly braces around blocks.
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pub struct Match(pub Fragment);
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impl ToTokens for Match {
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fn to_tokens(&self, out: &mut Tokens) {
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match self.0 {
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Fragment::Expr(ref expr) => {
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expr.to_tokens(out);
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out.append(",");
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}
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Fragment::Block(ref block) => {
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out.append("{");
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block.to_tokens(out);
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out.append("}");
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}
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}
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}
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}
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