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ast/cgen/parser: combine IfExpr branches into single node

pull/4078/head
Joe Conigliaro 2020-03-21 00:39:56 +11:00
parent c993489fe9
commit a331abf675
7 changed files with 182 additions and 167 deletions
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23
vlib/v/ast/ast.v
View File

@ -336,16 +336,21 @@ mut:
pub struct IfExpr {
pub:
tok_kind token.Kind
cond Expr
stmts []Stmt
else_stmts []Stmt
left Expr // `a` in `a := if ...`
pos token.Position
tok_kind token.Kind
branches []IfBranch
left Expr // `a` in `a := if ...`
pos token.Position
mut:
is_expr bool
typ table.Type
has_else bool
is_expr bool
typ table.Type
has_else bool
}
pub struct IfBranch {
pub:
cond Expr
stmts []Stmt
pos token.Position
}
pub struct MatchExpr {

46
vlib/v/checker/checker.v
View File

@ -909,32 +909,34 @@ pub fn (c mut Checker) if_expr(node mut ast.IfExpr) table.Type {
// println('$c.file.path $node.pos.line_nr IF: checker exp type = ' + sym.name)
node.is_expr = true
}
typ := c.expr(node.cond)
node.typ = table.void_type
// node.typ = typ
typ_sym := c.table.get_type_symbol(typ)
// if typ_sym.kind != .bool {
if table.type_idx(typ) != table.bool_type_idx {
c.error('non-bool (`$typ_sym.name`) used as if condition', node.pos)
}
c.stmts(node.stmts)
if node.else_stmts.len > 0 {
c.stmts(node.else_stmts)
}
if node.stmts.len > 0 {
match node.stmts[node.stmts.len - 1] {
ast.ExprStmt {
// type_sym := p.table.get_type_symbol(it.typ)
// p.warn('if expr ret $type_sym.name')
t := c.expr(it.expr)
node.typ = t
return t
for i, branch in node.branches {
typ := c.expr(branch.cond)
if i < node.branches.len-1 || !node.has_else {
typ_sym := c.table.get_type_symbol(typ)
// if typ_sym.kind != .bool {
if table.type_idx(typ) != table.bool_type_idx {
c.error('non-bool (`$typ_sym.name`) used as if condition', node.pos)
}
else {}
}
c.stmts(branch.stmts)
}
if node.has_else && node.is_expr {
last_branch := node.branches[node.branches.len-1]
if last_branch.stmts.len > 0 {
match last_branch.stmts[last_branch.stmts.len - 1] {
ast.ExprStmt {
// type_sym := p.table.get_type_symbol(it.typ)
// p.warn('if expr ret $type_sym.name')
t := c.expr(it.expr)
node.typ = t
return t
}
else {}
}
}
}
return typ
// return table.void_type
return table.bool_type
}
pub fn (c mut Checker) postfix_expr(node ast.PostfixExpr) table.Type {

42
vlib/v/fmt/fmt.v
View File

@ -378,38 +378,38 @@ fn (f mut Fmt) expr(node ast.Expr) {
f.write(it.val)
}
ast.IfExpr {
single_line := it.stmts.len == 1 && it.else_stmts.len == 1 && it.typ != table.void_type
single_line := it.branches.len == 2 && it.has_else //
&& it.branches[0].stmts.len == 1 && it.branches[1].stmts.len == 1
f.single_line_if = single_line
f.write('if ')
f.expr(it.cond)
if single_line {
f.write(' { ')
}
else {
f.writeln(' {')
}
f.stmts(it.stmts)
if single_line {
f.write(' ')
}
f.write('}')
if it.has_else {
f.write(' else ')
}
else if it.else_stmts.len > 0 {
f.write(' else {')
for i, branch in it.branches {
if i == 0 {
f.write('if ')
f.expr(branch.cond)
f.write(' {')
}
else if i < it.branches.len-1 || !it.has_else {
f.write('} else if ')
f.expr(branch.cond)
f.write(' {')
}
else if i == it.branches.len-1 && it.has_else {
f.write('} else {')
}
if single_line {
f.write(' ')
}
else {
f.writeln('')
}
f.stmts(it.else_stmts)
f.stmts(branch.stmts)
if single_line {
f.write(' ')
}
f.write('}')
}
// if !single_line {
// f.writeln('')
// }
f.write('}')
f.single_line_if = false
}
ast.Ident {

90
vlib/v/gen/cgen.v
View File

@ -1176,64 +1176,68 @@ fn (g mut Gen) if_expr(node ast.IfExpr) {
}
// one line ?:
// TODO clean this up once `is` is supported
if node.is_expr && node.stmts.len == 1 && node.else_stmts.len == 1 && type_sym.kind != .void {
cond := node.cond
stmt1 := node.stmts[0]
else_stmt1 := node.else_stmts[0]
match stmt1 {
ast.ExprStmt {
g.inside_ternary = true
g.expr(cond)
g.write(' ? ')
expr_stmt := stmt1 as ast.ExprStmt
g.expr(expr_stmt.expr)
// TODO: make sure only one stmt in eac branch
if node.is_expr && node.branches.len >= 2 && node.has_else && type_sym.kind != .void {
g.inside_ternary = true
for i, branch in node.branches {
if i > 0 {
g.write(' : ')
g.stmt(else_stmt1)
}
else {}
}
if i < node.branches.len-1 || !node.has_else {
g.expr(branch.cond)
g.write(' ? ')
}
g.stmts(branch.stmts)
}
g.inside_ternary = false
}
else {
mut is_guard := false
guard_ok := g.new_tmp_var()
match node.cond {
ast.IfGuardExpr {
is_guard = true
g.writeln('bool $guard_ok;')
g.write('{ /* if guard */ ${g.typ(it.expr_type)} $it.var_name = ')
g.expr(it.expr)
g.writeln(';')
g.writeln('if (($guard_ok = ${it.var_name}.ok)) {')
mut is_guard := false
for i, branch in node.branches {
if i == 0 {
match branch.cond {
ast.IfGuardExpr {
is_guard = true
g.writeln('bool $guard_ok;')
g.write('{ /* if guard */ ${g.typ(it.expr_type)} $it.var_name = ')
g.expr(it.expr)
g.writeln(';')
g.writeln('if (($guard_ok = ${it.var_name}.ok)) {')
}
else {
g.write('if (')
g.expr(branch.cond)
g.writeln(') {')
}
}
}
else {
g.inside_ternary = false
g.write('if (')
g.expr(node.cond)
g.writeln(') {')
else if i < node.branches.len-1 || !node.has_else {
g.writeln('} else if (')
g.expr(branch.cond)
g.write(') {')
}
else if i == node.branches.len-1 && node.has_else {
if is_guard {
g.writeln('} if (!$guard_ok) { /* else */')
}
else {
g.writeln('} else {')
}
}
}
for i, stmt in node.stmts {
// Assign ret value
if i == node.stmts.len - 1 && type_sym.kind != .void {}
// if i == node.stmts.len - 1 && type_sym.kind != .void {}
// g.writeln('$tmp =')
g.stmt(stmt)
//
g.stmts(branch.stmts)
// g.writeln('')
}
if is_guard {
g.write('}')
}
g.writeln('}')
if node.else_stmts.len > 0 {
if is_guard {
g.writeln('if (!$guard_ok) { /* else */')
}
else {
g.writeln('else { ')
}
g.stmts(node.else_stmts)
g.writeln('}')
}
}
g.inside_ternary = false
}
fn (g mut Gen) index_expr(node ast.IndexExpr) {

28
vlib/v/gen/jsgen.v
View File

@ -34,6 +34,12 @@ pub fn (g mut JsGen) writeln(s string) {
g.out.writeln(s)
}
fn (g mut JsGen) stmts(stmts []ast.Stmt) {
for stmt in stmts {
g.stmt(stmt)
}
}
fn (g mut JsGen) stmt(node ast.Stmt) {
match node {
ast.FnDecl {
@ -163,13 +169,23 @@ fn (g mut JsGen) expr(node ast.Expr) {
}
}
ast.IfExpr {
g.write('if (')
g.expr(it.cond)
g.writeln(') {')
for stmt in it.stmts {
g.stmt(stmt)
for i, branch in it.branches {
if i == 0 {
g.write('if (')
g.expr(branch.cond)
g.writeln(') {')
}
else if i < it.branches.len-1 || !it.has_else {
g.write('else if (')
g.expr(branch.cond)
g.writeln(') {')
}
else {
g.write('else {')
}
g.stmts(branch.stmts)
g.writeln('}')
}
g.writeln('}')
}
else {
println(term.red('jsgen.expr(): bad node'))

2
vlib/v/gen/tests/2.c
View File

@ -52,7 +52,7 @@ void function2() {
}
if (false) {
foo(1);
} else {
} else {
puts(tos3("else"));
foo(100);
}

118
vlib/v/parser/parser.v
View File

@ -1175,82 +1175,70 @@ fn (p mut Parser) for_statement() ast.Stmt {
}
}
fn (p mut Parser) if_expr() ast.Expr {
fn (p mut Parser) if_expr() ast.IfExpr {
p.inside_if = true
// defer {
// }
mut node := ast.Expr{}
p.check(.key_if)
pos := p.tok.position()
// `if x := opt() {`
mut cond := ast.Expr{}
mut is_or := false
if p.peek_tok.kind == .decl_assign {
is_or = true
p.open_scope()
var_name := p.check_name()
p.check(.decl_assign)
expr := p.expr(0)
p.scope.register_var(ast.Var{
name: var_name
expr: expr
})
cond = ast.IfGuardExpr{
var_name: var_name
expr: expr
}
}
else {
cond = p.expr(0)
}
p.inside_if = false
mut branches := []ast.IfBranch
mut has_else := false
stmts := p.parse_block()
mut else_stmts := []ast.Stmt
if p.tok.kind == .key_else {
p.check(.key_else)
for p.tok.kind in [.key_if, .key_else] {
branch_pos := p.tok.position()
if p.tok.kind == .key_if {
// The next if block is handled by next if_expr()
has_else = true
p.check(.key_if)
}
// p.if_expr()
else {
else_stmts = p.parse_block()
p.check(.key_else)
if p.tok.kind == .key_if {
p.check(.key_if)
}
else {
has_else = true
branches << ast.IfBranch{
stmts: p.parse_block()
pos: branch_pos
}
break
}
}
mut cond := ast.Expr{}
mut is_or := false
// `if x := opt() {`
if p.peek_tok.kind == .decl_assign {
is_or = true
p.open_scope()
var_name := p.check_name()
p.check(.decl_assign)
expr := p.expr(0)
p.scope.register_var(ast.Var{
name: var_name
expr: expr
})
cond = ast.IfGuardExpr{
var_name: var_name
expr: expr
}
}
else {
cond = p.expr(0)
}
p.inside_if = false
stmts := p.parse_block()
if is_or {
p.close_scope()
}
branches << ast.IfBranch{
cond: cond
stmts: stmts
pos: branch_pos
}
if p.tok.kind != .key_else {
break
}
}
if is_or {
p.close_scope()
}
// mut typ := table.void_type
// mut left := ast.Expr{}
// If the last statement is an expression, return its type
/*
if stmts.len > 0 {
match stmts[stmts.len - 1] {
ast.ExprStmt {
type_sym := p.table.get_type_symbol(it.typ)
p.warn('if expr ret $type_sym.name')
typ = it.typ
// return node,it.ti
// left =
}
else {}
}
}
*/
node = ast.IfExpr{
cond: cond
stmts: stmts
else_stmts: else_stmts
// typ: typ
return ast.IfExpr{
branches: branches
pos: pos
has_else: has_else
// left: left
}
return node
}
fn (p mut Parser) string_expr() ast.Expr {