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//! code generation for trashcan statements
use std::io;
use std::io::Write;
use ast::*;
use super::*;
#[derive(Copy, Clone, Debug)]
pub enum ExprPos {
/// used as expression
Expr,
/// used as statement (i.e. fn call or member invoke with no/discarded
/// return value)
Stmt,
}
impl Emit<ExprPos> for Expr {
fn emit<W: Write>(&self, out: &mut W, symtab: &SymbolTable,
ctxt: ExprPos, indent: u32) -> io::Result<()> {
match self.data {
ExprKind::Lit(ref literal) => literal.emit(out, symtab, (), indent),
ExprKind::Name(ref path) => {
path.emit(out, symtab, (), indent)
},
ExprKind::Index(ref expr, ref indices) => {
expr.emit(out, symtab, ExprPos::Expr, indent)?;
out.write_all(b"(")?;
for (i, index) in indices.iter().enumerate() {
if i != 0 {
out.write_all(b", ")?;
}
index.emit(out, symtab, ExprPos::Expr, 0)?;
}
out.write_all(b")")
},
ExprKind::Call(ref path, ref args, ref optargs) => {
path.emit(out, symtab, (), indent)?;
match ctxt {
ExprPos::Expr => out.write_all(b"(")?,
ExprPos::Stmt => out.write_all(b" ")?,
};
for (i, arg) in args.iter().enumerate() {
if i != 0 { out.write_all(b", ")?; }
arg.emit(out, symtab, ExprPos::Expr, 0)?;
}
if !args.is_empty() && !optargs.is_empty() {
out.write_all(b", ")?;
}
for (i, &(ref name, ref arg)) in optargs.iter().enumerate() {
if i != 0 { out.write_all(b", ")?; }
name.emit(out, symtab, (), 0)?;
out.write_all(b" := ")?;
arg.emit(out, symtab, ExprPos::Expr, 0)?;
}
match ctxt {
ExprPos::Expr => out.write_all(b")")?,
ExprPos::Stmt => {},
};
Ok(())
},
ExprKind::Member(ref expr, ref member) => {
expr.emit(out, symtab, ctxt, indent)?;
out.write_all(b".")?;
member.emit(out, symtab, (), 0)
},
ExprKind::MemberInvoke(ref expr, ref member, ref args) => {
expr.emit(out, symtab, ctxt, indent)?;
out.write_all(b".")?;
member.emit(out, symtab, (), 0)?;
match ctxt {
ExprPos::Expr => out.write_all(b"(")?,
ExprPos::Stmt => out.write_all(b" ")?,
};
for (i, arg) in args.iter().enumerate() {
if i != 0 { out.write_all(b", ")?; }
arg.emit(out, symtab, ExprPos::Expr, 0)?;
}
match ctxt {
ExprPos::Expr => out.write_all(b")")?,
ExprPos::Stmt => {},
};
Ok(())
},
ExprKind::UnOpApp(ref expr, ref op) => {
write!(out, "{:in$}", "", in = (indent * INDENT) as usize)?;
match *op {
UnOp::Negate => {
out.write_all(b"-")?;
expr.emit(out, symtab, ctxt, 0)?;
},
UnOp::BitNot | UnOp::LogNot => {
out.write_all(b"Not ")?;
expr.emit(out, symtab, ctxt, 0)?;
},
UnOp::AddressOf => {
let expr_ty = expr.ty.as_ref()
.expect("dumpster fire: untyped expression \
in codegen");
match *expr_ty {
Type::Obj | Type::Object(_) =>
out.write_all(b"ObjPtr(")?,
_ => out.write_all(b"VarPtr(")?,
};
expr.emit(out, symtab, ctxt, 0)?;
out.write_all(b")")?;
},
};
Ok(())
},
ExprKind::BinOpApp(ref lhs, ref rhs, ref op) => {
// no infix "IsNot" in VB6; convert to Not (... Is ...)
let op = match *op {
BinOp::NotIdentEq => {
write!(out, "{:in$}Not (", "",
in = (indent * INDENT) as usize)?;
BinOp::IdentEq
},
// wacky special case: if we have a division, and both
// operands are definitely of integral type, we need
// to emit a '\' integer-divide op
// TODO: should we handle this with an AST node and a
// rewriter?
BinOp::Div => {
write!(out, "{:in$}(", "",
in = (indent * INDENT) as usize)?;
let lhs_ty = lhs.ty.as_ref()
.expect("dumpster fire: untyped expression \
in codegen");
let rhs_ty = rhs.ty.as_ref()
.expect("dumpster fire: untyped expression \
in codegen");
if lhs_ty.is_integral() && rhs_ty.is_integral() {
lhs.emit(out, symtab, ctxt, 0)?;
out.write_all(b" \\ ")?;
rhs.emit(out, symtab, ctxt, 0)?;
return out.write_all(b")")
} else {
BinOp::Div // use normal-case code
}
},
op => {
write!(out, "{:in$}(", "",
in = (indent * INDENT) as usize)?;
op
},
};
lhs.emit(out, symtab, ctxt, 0)?;
op.emit(out, symtab, (), 0)?;
rhs.emit(out, symtab, ctxt, 0)?;
out.write_all(b")")
},
ExprKind::CondExpr { .. } => {
panic!("dumpster fire: raw CondExpr in codegen");
},
ExprKind::ExtentExpr(ref expr, kind, dim) => {
let expr_ty = expr.ty.as_ref()
.expect("dumpster fire: untyped expression \
in codegen");
let emit_dim = match *expr_ty {
Type::Array(_, ref bounds) => bounds.dims() != 1,
Type::VarArgsArray => false,
// TODO: maybe allow variants here (checked at runtime)?
_ => panic!("dumpster fire: non-array expression \
in extent expr"),
};
write!(out, "{:in$}", "", in = (indent * INDENT) as usize)?;
match kind {
ExtentKind::First => {
out.write_all(b"LBound(")?;
expr.emit(out, symtab, ctxt, 0)?;
if emit_dim {
write!(out, ", {})", dim + 1)
} else {
out.write_all(b")")
}
},
ExtentKind::Last => {
out.write_all(b"UBound(")?;
expr.emit(out, symtab, ctxt, 0)?;
if emit_dim {
write!(out, ", {})", dim + 1)
} else {
out.write_all(b")")
}
},
// TODO: would it be cleaner to handle this in a rewriter?
ExtentKind::Length => {
out.write_all(b"(UBound(")?;
expr.emit(out, symtab, ctxt, 0)?;
if emit_dim {
write!(out, ", {}) - LBound(", dim + 1)?;
} else {
out.write_all(b") - LBound(")?;
}
expr.emit(out, symtab, ctxt, 0)?;
if emit_dim {
write!(out, ", {}) + 1)", dim + 1)
} else {
out.write_all(b") + 1)")
}
},
}
},
ExprKind::Cast(ref expr, ref ty) => {
let cast_op = match *ty {
Type::UInt8 => "CByte",
Type::Int16 => "CInt",
Type::Int32 => "CLng",
Type::IntPtr => "CLngPtr",
Type::Float32 => "CSng",
Type::Float64 => "CDbl",
Type::String => "CStr",
Type::Currency => "CCur",
Type::Date => "CDate",
Type::Variant => "CVar",
ref ty => panic!("dumpster fire: bad (or untransformed) \
cast to {} in codegen", ty)
};
write!(out, "{:in$}{}(", "", cast_op,
in = (indent * INDENT) as usize)?;
expr.emit(out, symtab, ctxt, 0)?;
out.write_all(b")")
},
ExprKind::VbExpr(ref bytes) => {
write!(out, "{:in$}", "", in = (indent * INDENT) as usize)?;
out.write_all(bytes)
},
}
}
}