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js: add initial support for optional types, IfGuardExpr codegen for `if` (#11332)

pull/11335/head
playX 2021-08-29 14:27:17 +03:00 committed by GitHub
parent 985fe85de2
commit 61ac7b671d
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 200 additions and 63 deletions
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6
vlib/builtin/js/builtin.js.v
View File

@ -44,3 +44,9 @@ pub fn exit(c int) {
JS.process.exit(c)
js_throw('exit($c)')
}
fn opt_ok(data voidptr, option Option) {
#option.state = 0
#option.err = none__
#option.data = data
}

15
vlib/builtin/js/builtin.v
View File

@ -19,11 +19,6 @@ pub fn panic(s string) {
exit(1)
}
struct Option {
state byte
err Error
}
// IError holds information about an error instance
pub interface IError {
msg string
@ -37,7 +32,12 @@ pub:
code int
}
const none__ = IError(&None__{})
pub const none__ = IError(&None__{})
pub struct Option {
state byte
err IError = none__
}
struct None__ {
msg string
@ -66,7 +66,6 @@ pub fn (o Option) str() string {
return 'Option{ error: "$o.err" }'
}
[if trace_error ?]
fn trace_error(x string) {
eprintln('> ${@FN} | $x')
}
@ -75,7 +74,7 @@ fn trace_error(x string) {
// Example: `if ouch { return error('an error occurred') }`
[inline]
pub fn error(message string) IError {
trace_error(message)
// trace_error(message)
return &Error{
msg: message
}

242
vlib/v/gen/js/js.v
View File

@ -63,6 +63,7 @@ mut:
inside_loop bool
inside_map_set bool // map.set(key, value)
inside_builtin bool
inside_if_optional bool
generated_builtin bool
inside_def_typ_decl bool
is_test bool
@ -891,12 +892,12 @@ fn (mut g JsGen) expr(node ast.Expr) {
ast.MapInit {
g.gen_map_init_expr(node)
}
ast.None {
g.write('builtin.none__')
}
ast.MatchExpr {
g.match_expr(node)
}
ast.None {
// TODO
}
ast.OrExpr {
// TODO
}
@ -1309,7 +1310,7 @@ fn (mut g JsGen) gen_enum_decl(it ast.EnumDecl) {
fn (mut g JsGen) gen_expr_stmt(it ast.ExprStmt) {
g.expr(it.expr)
if !it.is_expr && it.expr !is ast.IfExpr && !g.inside_ternary {
if !it.is_expr && it.expr !is ast.IfExpr && !g.inside_ternary && !g.inside_if_optional {
g.writeln(';')
}
}
@ -1623,12 +1624,43 @@ fn (mut g JsGen) gen_interface_decl(it ast.InterfaceDecl) {
g.writeln('function ${g.js_name(it.name)} (arg) { return arg; }')
}
fn (mut g JsGen) gen_optional_error(expr ast.Expr) {
g.write('new builtin.Option({ state: new builtin.byte(2),err: ')
g.expr(expr)
g.write('})')
}
fn (mut g JsGen) gen_return_stmt(it ast.Return) {
if it.exprs.len == 0 {
// Returns nothing
g.writeln('return;')
node := it
// sym := g.table.get_type_symbol(g.fn_decl.return_type)
fn_return_is_optional := g.fn_decl.return_type.has_flag(.optional)
if node.exprs.len == 0 {
if fn_return_is_optional {
g.writeln('return {}')
} else {
g.writeln('return;')
}
return
}
if fn_return_is_optional {
optional_none := node.exprs[0] is ast.None
ftyp := g.typ(node.types[0])
mut is_regular_option := ftyp == 'Option'
if optional_none || is_regular_option || node.types[0] == ast.error_type_idx {
if !isnil(g.fn_decl) && g.fn_decl.is_test {
test_error_var := g.new_tmp_var()
g.writeln('let $test_error_var = "TODO";')
g.writeln('return $test_error_var;')
return
}
g.write('return ')
g.gen_optional_error(it.exprs[0])
g.writeln(';')
return
}
}
g.write('return ')
if it.exprs.len == 1 {
g.expr(it.exprs[0])
@ -2240,11 +2272,29 @@ fn (mut g JsGen) stmts_with_tmp_var(stmts []ast.Stmt, tmp_var string) {
}
for i, stmt in stmts {
if i == stmts.len - 1 && tmp_var != '' {
g.write('$tmp_var = ')
g.stmt(stmt)
g.writeln('')
if g.inside_if_optional {
if stmt is ast.ExprStmt {
if stmt.typ == ast.error_type_idx || stmt.expr is ast.None {
g.writeln('${tmp_var}.state = 2;')
g.write('${tmp_var}.err = ')
g.expr(stmt.expr)
g.writeln(';')
} else {
g.write('builtin.opt_ok(')
g.stmt(stmt)
g.writeln(', $tmp_var);')
}
}
} else {
g.write('$tmp_var = ')
g.stmt(stmt)
g.writeln('')
}
} else {
g.stmt(stmt)
if g.inside_if_optional && stmt is ast.ExprStmt {
g.writeln(';')
}
}
if g.inside_ternary && i < stmts.len - 1 {
g.write(',')
@ -2308,16 +2358,58 @@ fn (mut g JsGen) match_expr_sumtype(node ast.MatchExpr, is_expr bool, cond_var M
}
}
fn (mut g JsGen) need_tmp_var_in_if(node ast.IfExpr) bool {
if node.is_expr && g.inside_ternary {
if node.typ.has_flag(.optional) {
return true
}
for branch in node.branches {
if branch.cond is ast.IfGuardExpr || branch.stmts.len > 1 {
return true
}
if branch.stmts.len == 1 {
if branch.stmts[0] is ast.ExprStmt {
stmt := branch.stmts[0] as ast.ExprStmt
if stmt.expr is ast.CallExpr {
if stmt.expr.is_method {
left_sym := g.table.get_type_symbol(stmt.expr.receiver_type)
if left_sym.kind in [.array, .array_fixed, .map] {
return true
}
}
}
}
}
}
}
return false
}
fn (mut g JsGen) gen_if_expr(node ast.IfExpr) {
if node.is_comptime {
g.comp_if(node)
return
}
type_sym := g.table.get_type_symbol(node.typ)
// one line ?:
if node.is_expr && node.branches.len >= 2 && node.has_else && type_sym.kind != .void {
// `x := if a > b { } else if { } else { }`
// For simpe if expressions we can use C's `?:`
// `if x > 0 { 1 } else { 2 }` => `(x > 0) ? (1) : (2)`
// For if expressions with multiple statements or another if expression inside, it's much
// easier to use a temp var, than do C tricks with commas, introduce special vars etc
// (as it used to be done).
// Always use this in -autofree, since ?: can have tmp expressions that have to be freed.
needs_tmp_var := g.need_tmp_var_in_if(node)
tmp := if needs_tmp_var { g.new_tmp_var() } else { '' }
if needs_tmp_var {
if node.typ.has_flag(.optional) {
g.inside_if_optional = true
}
g.writeln('let $tmp; /* if prepend */')
} else if node.is_expr || g.inside_ternary {
g.write('(')
prev := g.inside_ternary
g.inside_ternary = true
for i, branch in node.branches {
if i > 0 {
@ -2326,60 +2418,100 @@ fn (mut g JsGen) gen_if_expr(node ast.IfExpr) {
if i < node.branches.len - 1 || !node.has_else {
g.write('(')
g.expr(branch.cond)
g.write(')')
g.write('.valueOf()')
g.write(').valueOf()')
g.write(' ? ')
}
g.stmts(branch.stmts)
}
g.inside_ternary = false
g.inside_ternary = prev
g.write(')')
} else {
// mut is_guard = false
for i, branch in node.branches {
if i == 0 {
match branch.cond {
ast.IfGuardExpr {
// TODO optionals
return
}
mut is_guard := false
mut guard_idx := 0
mut guard_vars := []string{}
for i, branch in node.branches {
cond := branch.cond
if cond is ast.IfGuardExpr {
if !is_guard {
is_guard = true
guard_idx = i
guard_vars = []string{len: node.branches.len}
}
if cond.expr !is ast.IndexExpr && cond.expr !is ast.PrefixExpr {
var_name := g.new_tmp_var()
guard_vars[i] = var_name
g.writeln('let $var_name;')
} else {
guard_vars[i] = ''
}
}
}
for i, branch in node.branches {
if i > 0 {
g.write('} else ')
}
// if last branch is `else {`
if i == node.branches.len - 1 && node.has_else {
g.writeln('{')
// define `err` only for simple `if val := opt {...} else {`
if is_guard && guard_idx == i - 1 {
cvar_name := guard_vars[guard_idx]
g.writeln('\tlet err = ${cvar_name}.err;')
}
} else {
match branch.cond {
ast.IfGuardExpr {
mut var_name := guard_vars[i]
mut short_opt := false
if var_name == '' {
short_opt = true // we don't need a further tmp, so use the one we'll get later
var_name = g.new_tmp_var()
guard_vars[i] = var_name // for `else`
g.tmp_count--
g.writeln('if (${var_name}.state == 0) {')
} else {
g.write('if ($var_name = ')
g.expr(branch.cond.expr)
g.writeln(', ${var_name}.state == 0) {')
}
else {
g.write('if (')
if '$branch.cond' == 'js' {
g.write('true')
if short_opt || branch.cond.var_name != '_' {
if short_opt {
cond_var_name := if branch.cond.var_name == '_' {
'_dummy_${g.tmp_count + 1}'
} else {
branch.cond.var_name
}
g.write('\tlet $cond_var_name = ')
g.expr(branch.cond.expr)
g.writeln(';')
} else {
g.write('(')
g.expr(branch.cond)
g.write(')')
g.write('.valueOf()')
g.writeln('\tlet $branch.cond.var_name = ${var_name}.data;')
}
g.writeln(') {')
}
}
} else if i < node.branches.len - 1 || !node.has_else {
g.write('} else if (')
g.write('(')
g.expr(branch.cond)
g.write(')')
g.write('.valueOf()')
g.writeln(') {')
} else if i == node.branches.len - 1 && node.has_else {
/*
if is_guard {
//g.writeln('} if (!$guard_ok) { /* else */')
} else {
*/
g.writeln('} else {')
// }
else {
g.write('if ((')
g.expr(branch.cond)
g.writeln(').valueOf()) {')
}
}
}
if needs_tmp_var {
g.stmts_with_tmp_var(branch.stmts, tmp)
} else {
g.stmts(branch.stmts)
}
/*
if is_guard {
g.write('}')
}
*/
g.writeln('}')
g.writeln('')
}
g.writeln('}')
if needs_tmp_var {
g.write('$tmp')
}
if node.typ.has_flag(.optional) {
g.inside_if_optional = false
}
}