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use crate::ast::{Block, Exp, PrefixExp};
use crate::compiler::Compiler;
use crate::error::Result;
use crate::vm::{Literal, OpCode};
impl Compiler {
pub(super) fn compile_block(&mut self, block: Block) -> Result<bool> {
for stat in block.stats {
self.compile_stat(stat)?;
}
Ok(if let Some((mut exps, pos)) = block.ret {
if !self.scopes.has_to_be_closed() && exps.len() == 1 {
let exp = exps.pop().unwrap();
match exp {
Exp::Prefix(PrefixExp::Call(pos_call, prefix, args)) => {
let ret_reg = self.compile_call(pos_call, *prefix, args, true)?;
self.code.emit(OpCode::Return { ret_reg }, pos);
self.scopes.reg_free(ret_reg);
}
Exp::Prefix(PrefixExp::CallMethod(pos_call, prefix, name, args)) => {
let ret_reg =
self.compile_call_method(pos_call, *prefix, name, args, true)?;
self.code.emit(OpCode::Return { ret_reg }, pos);
self.scopes.reg_free(ret_reg);
}
exp => {
let ret_reg = self.scopes.reg_reserve();
self.code.emit(
OpCode::Lit {
val: Literal::Empty,
dst_reg: ret_reg,
},
pos,
);
let exp_reg = self.compile_exp(exp)?;
self.code.emit(
OpCode::Extend {
src_reg: exp_reg,
dst_reg: ret_reg,
},
pos,
);
self.scopes.reg_free(exp_reg);
self.code.emit(OpCode::Return { ret_reg }, pos);
self.scopes.reg_free(ret_reg);
}
}
} else {
let ret_reg = self.scopes.reg_reserve();
self.code.emit(
OpCode::Lit {
val: Literal::Empty,
dst_reg: ret_reg,
},
pos,
);
let last = exps.pop();
for exp in exps.into_iter() {
let exp_reg = self.compile_exp(exp)?;
self.code.emit(OpCode::Single { reg: exp_reg }, pos);
self.code.emit(
OpCode::Append {
src_reg: exp_reg,
dst_reg: ret_reg,
},
pos,
);
self.scopes.reg_free(exp_reg);
}
if let Some(exp) = last {
let exp_reg = self.compile_exp(exp)?;
self.code.emit(
OpCode::Extend {
src_reg: exp_reg,
dst_reg: ret_reg,
},
pos,
);
self.scopes.reg_free(exp_reg);
}
self.code.emit(OpCode::Return { ret_reg }, pos);
self.scopes.reg_free(ret_reg);
}
true
} else {
false
})
}
}