js: match support (#11269)

pull/11276/head
playX 2021-08-22 19:36:49 +03:00 committed by GitHub
parent b80777df4b
commit dd486bb0fb
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3 changed files with 309 additions and 3 deletions

View File

@ -713,7 +713,7 @@ fn (mut g JsGen) expr(node ast.Expr) {
g.gen_map_init_expr(node)
}
ast.MatchExpr {
// TODO
g.match_expr(node)
}
ast.None {
// TODO
@ -801,8 +801,10 @@ fn (mut g JsGen) expr(node ast.Expr) {
g.gen_struct_init(node)
}
ast.TypeNode {
// skip: JS has no types
// TODO maybe?
typ := g.unwrap_generic(node.typ)
sym := g.table.get_type_symbol(typ)
name := sym.name.replace_once('${g.ns.name}.', '')
g.write('$name')
}
ast.Likely {
g.write('(')
@ -1734,6 +1736,249 @@ fn (mut g JsGen) gen_lock_expr(node ast.LockExpr) {
// TODO: implement this
}
fn (mut g JsGen) need_tmp_var_in_match(node ast.MatchExpr) bool {
if node.is_expr && node.return_type != ast.void_type && node.return_type != 0 {
sym := g.table.get_type_symbol(node.return_type)
if sym.kind == .multi_return {
return false
}
for branch in node.branches {
if 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 || stmt.expr is ast.IfExpr
|| stmt.expr is ast.MatchExpr || (stmt.expr is ast.IndexExpr
&& (stmt.expr as ast.IndexExpr).or_expr.kind != .absent) {
return true
}
}
}
}
}
return false
}
fn (mut g JsGen) match_expr_classic(node ast.MatchExpr, is_expr bool, cond_var string, tmp_var string) {
type_sym := g.table.get_type_symbol(node.cond_type)
for j, branch in node.branches {
is_last := j == node.branches.len - 1
if branch.is_else || (node.is_expr && is_last && tmp_var.len == 0) {
if node.branches.len > 1 {
if is_expr && tmp_var.len == 0 {
// TODO too many branches. maybe separate ?: matches
g.write(' : ')
} else {
g.writeln('')
g.write_v_source_line_info(branch.pos)
g.writeln('else {')
}
}
} else {
if j > 0 {
if is_expr && tmp_var.len == 0 {
g.write(' : ')
} else {
g.writeln('')
g.write_v_source_line_info(branch.pos)
g.write('else ')
}
}
if is_expr && tmp_var.len == 0 {
g.write('(')
} else {
if j == 0 {
g.writeln('')
}
g.write_v_source_line_info(branch.pos)
g.write('if (')
}
for i, expr in branch.exprs {
if i > 0 {
g.write(' || ')
}
match type_sym.kind {
.array {
g.write('vEq($cond_var, ')
g.expr(expr)
g.write(')')
}
.array_fixed {
g.write('vEq($cond_var, ')
g.expr(expr)
g.write(')')
}
.map {
g.write('vEq($cond_var, ')
g.expr(expr)
g.write(')')
}
.string {
g.write('vEq($cond_var, ')
g.expr(expr)
g.write(')')
}
.struct_ {
g.write('vEq($cond_var, ')
g.expr(expr)
g.write(')')
}
else {
if expr is ast.RangeExpr {
// if type is unsigned and low is 0, check is unneeded
mut skip_low := false
if expr.low is ast.IntegerLiteral {
if node.cond_type in [ast.u16_type, ast.u32_type, ast.u64_type]
&& expr.low.val == '0' {
skip_low = true
}
}
g.write('(')
if !skip_low {
g.write('$cond_var >= ')
g.expr(expr.low)
g.write(' && ')
}
g.write('$cond_var <= ')
g.expr(expr.high)
g.write(')')
} else {
g.write('vEq($cond_var,')
g.expr(expr)
g.write(')')
}
}
}
}
if is_expr && tmp_var.len == 0 {
g.write(') ? ')
} else {
g.writeln(') {')
}
}
g.stmts_with_tmp_var(branch.stmts, tmp_var)
if !g.inside_ternary && node.branches.len >= 1 {
g.write('}')
}
}
}
fn (mut g JsGen) match_expr(node ast.MatchExpr) {
if node.cond_type == 0 {
g.writeln('// match 0')
return
}
prev := g.inside_ternary
need_tmp_var := g.need_tmp_var_in_match(node)
is_expr := (node.is_expr && node.return_type != ast.void_type) || g.inside_ternary
mut cond_var := ''
mut tmp_var := ''
if is_expr && !need_tmp_var {
g.inside_ternary = true
}
cond_var = g.new_tmp_var()
g.write('let $cond_var = ')
g.expr(node.cond)
g.write(';')
if need_tmp_var {
tmp_var = g.new_tmp_var()
g.writeln('let $tmp_var = undefined;')
}
if is_expr && !need_tmp_var {
g.write('(')
}
if node.is_sum_type {
g.match_expr_sumtype(node, is_expr, cond_var, tmp_var)
} else {
g.match_expr_classic(node, is_expr, cond_var, tmp_var)
}
if need_tmp_var {
g.write('$tmp_var')
}
if is_expr && !need_tmp_var {
g.write(')')
g.inside_ternary = prev
}
}
fn (mut g JsGen) stmts_with_tmp_var(stmts []ast.Stmt, tmp_var string) {
g.inc_indent()
if g.inside_ternary {
g.write('(')
}
for i, stmt in stmts {
if i == stmts.len - 1 && tmp_var != '' {
g.write('$tmp_var = ')
g.stmt(stmt)
g.writeln('')
} else {
g.stmt(stmt)
}
if g.inside_ternary && i < stmts.len - 1 {
g.write(',')
}
}
g.dec_indent()
if g.inside_ternary {
g.write(')')
}
}
fn (mut g JsGen) match_expr_sumtype(node ast.MatchExpr, is_expr bool, cond_var string, tmp_var string) {
for j, branch in node.branches {
mut sumtype_index := 0
for {
is_last := j == node.branches.len - 1
sym := g.table.get_type_symbol(node.cond_type)
if branch.is_else || (node.is_expr && is_last && tmp_var.len == 0) {
if is_expr && tmp_var.len == 0 {
g.write(' : ')
} else {
g.writeln('')
g.writeln('else {')
}
} else {
if j > 0 || sumtype_index > 0 {
if is_expr && tmp_var.len == 0 {
g.write(' : ')
} else {
g.write('else ')
}
}
if is_expr && tmp_var.len == 0 {
g.write('(')
} else {
g.write('if (')
}
g.write(cond_var)
if sym.kind == .sum_type {
g.write(' instanceof ')
g.expr(branch.exprs[sumtype_index])
} else {
panic('TODO: Generate match for interfaces')
}
if is_expr && tmp_var.len == 0 {
g.write(') ? ')
} else {
g.writeln(') {')
}
}
g.stmts_with_tmp_var(branch.stmts, tmp_var)
if !g.inside_ternary {
g.writeln('}')
}
sumtype_index++
if branch.exprs.len == 0 || sumtype_index == branch.exprs.len {
break
}
}
}
}
fn (mut g JsGen) gen_if_expr(node ast.IfExpr) {
if node.is_comptime {
g.comp_if(node)

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@ -0,0 +1,4 @@
Vec2d(42,43)
Vec2d(46,74,21)
life
V is running on JS

View File

@ -0,0 +1,57 @@
struct Vec2d {
x int
y int
}
struct Vec3d {
x int
y int
z int
}
type Vec = Vec2d | Vec3d
fn match_vec(v Vec) {
match v {
Vec2d {
println('Vec2d($v.x,$v.y)')
}
Vec3d {
println('Vec2d($v.x,$v.y,$v.z)')
}
}
}
fn match_classic_num() {
match 42 {
0 {
assert (false)
}
1 {
assert (false)
}
42 {
println('life')
}
else {
assert (false)
}
}
}
fn match_classic_string() {
os := 'JS'
print('V is running on ')
match os {
'darwin' { println('macOS.') }
'linux' { println('Linux.') }
else { println(os) }
}
}
fn main() {
match_vec(Vec2d{42, 43})
match_vec(Vec3d{46, 74, 21})
match_classic_num()
match_classic_string()
}