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refactor: Remove some duplication from the reduce action

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This commit is contained in:
Markus Westerlind 2018-02-04 14:54:58 +01:00
parent 4f0a7a6a49
commit 63183f67c6
1 changed files with 21 additions and 14 deletions
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35
lalrpop/src/lr1/codegen/parse_table.rs
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@ -761,9 +761,8 @@ impl<'ascent, 'grammar, W: Write> CodeGenerator<'ascent, 'grammar, W, TableDrive
rust!(self.out, "{{"); rust!(self.out, "{{");
rust!(self.out, rust!(self.out,
"let {}nonterminal = match -{}action {{", "let ({p}pop_states, {p}symbol, {p}nonterminal) = match -{}action {{",
self.prefix, p = self.prefix);
self.prefix);
for (production, index) in self.grammar for (production, index) in self.grammar
.nonterminals .nonterminals
.values() .values()
@ -778,6 +777,20 @@ impl<'ascent, 'grammar, W: Write> CodeGenerator<'ascent, 'grammar, W, TableDrive
"_ => panic!(\"invalid action code {{}}\", {}action)", "_ => panic!(\"invalid action code {{}}\", {}action)",
self.prefix); self.prefix);
rust!(self.out, "}};"); rust!(self.out, "}};");
// pop the consumed states from the stack
rust!(self.out,
"let {p}states_len = {p}states.len();",
p = self.prefix);
rust!(self.out,
"{p}states.truncate({p}states_len - {p}pop_states);",
p = self.prefix);
rust!(self.out,
"{p}symbols.push({p}symbol);",
p = self.prefix);
rust!(self.out, rust!(self.out,
"let {}state = *{}states.last().unwrap() as usize;", "let {}state = *{}states.last().unwrap() as usize;",
self.prefix, self.prefix,
@ -900,19 +913,10 @@ impl<'ascent, 'grammar, W: Write> CodeGenerator<'ascent, 'grammar, W, TableDrive
return Ok(()); return Ok(());
} }
// pop the consumed states from the stack
rust!(self.out,
"let {p}states_len = {p}states.len();",
p = self.prefix);
rust!(self.out,
"{p}states.truncate({p}states_len - {len});",
p = self.prefix,
len = production.symbols.len());
// push the produced value on the stack // push the produced value on the stack
let name = self.variant_name_for_symbol(&Symbol::Nonterminal(production.nonterminal.clone())); let name = self.variant_name_for_symbol(&Symbol::Nonterminal(production.nonterminal.clone()));
rust!(self.out, rust!(self.out,
"{}symbols.push(({}start, {}Symbol::{}({}nt), {}end));", "let {}symbol = ({}start, {}Symbol::{}({}nt), {}end);",
self.prefix, self.prefix,
self.prefix, self.prefix,
self.prefix, self.prefix,
@ -927,7 +931,10 @@ impl<'ascent, 'grammar, W: Write> CodeGenerator<'ascent, 'grammar, W, TableDrive
.iter() .iter()
.position(|x| *x == production.nonterminal) .position(|x| *x == production.nonterminal)
.unwrap(); .unwrap();
rust!(self.out, "{}", index); rust!(self.out, "({len}, {p}symbol, {index})",
p = self.prefix,
index = index,
len = production.symbols.len());
Ok(()) Ok(())
} }