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assign.v
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assign.v
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// Copyright (c) 2019-2023 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module parser
import v.ast
fn (mut p Parser) assign_stmt() ast.Stmt {
mut defer_vars := p.defer_vars.clone()
p.defer_vars = []ast.Ident{}
exprs, comments := p.expr_list()
if !(p.inside_defer && p.tok.kind == .decl_assign) {
defer_vars << p.defer_vars
}
p.defer_vars = defer_vars
return p.partial_assign_stmt(exprs, comments)
}
const max_expr_level = 100
fn (mut p Parser) check_undefined_variables(names []string, val ast.Expr) ! {
p.expr_level++
defer {
p.expr_level--
}
if p.expr_level > parser.max_expr_level {
return error('expr level > ${parser.max_expr_level}')
}
match val {
ast.Ident {
for name in names {
if name == val.name && val.kind != .blank_ident {
p.error_with_pos('undefined variable: `${val.name}`', val.pos)
return error('undefined variable: `${val.name}`')
}
}
}
ast.ArrayInit {
if val.has_cap {
p.check_undefined_variables(names, val.cap_expr)!
}
if val.has_len {
p.check_undefined_variables(names, val.len_expr)!
}
if val.has_default {
p.check_undefined_variables(names, val.default_expr)!
}
for expr in val.exprs {
p.check_undefined_variables(names, expr)!
}
}
ast.CallExpr {
p.check_undefined_variables(names, val.left)!
for arg in val.args {
p.check_undefined_variables(names, arg.expr)!
}
}
ast.CastExpr {
p.check_undefined_variables(names, val.expr)!
p.check_undefined_variables(names, val.arg)!
}
ast.IndexExpr {
p.check_undefined_variables(names, val.left)!
p.check_undefined_variables(names, val.index)!
}
ast.InfixExpr {
p.check_undefined_variables(names, val.left)!
p.check_undefined_variables(names, val.right)!
}
ast.IfExpr {
p.check_undefined_variables(names, val.left)!
for branch in val.branches {
p.check_undefined_variables(names, branch.cond)!
for stmt in branch.stmts {
if stmt is ast.ExprStmt {
p.check_undefined_variables(names, stmt.expr)!
}
}
}
}
ast.MapInit {
for key in val.keys {
p.check_undefined_variables(names, key)!
}
for value in val.vals {
p.check_undefined_variables(names, value)!
}
}
ast.MatchExpr {
p.check_undefined_variables(names, val.cond)!
for branch in val.branches {
for expr in branch.exprs {
p.check_undefined_variables(names, expr)!
}
for stmt in branch.stmts {
if stmt is ast.ExprStmt {
p.check_undefined_variables(names, stmt.expr)!
}
}
}
}
ast.ParExpr {
p.check_undefined_variables(names, val.expr)!
}
ast.PostfixExpr {
p.check_undefined_variables(names, val.expr)!
}
ast.PrefixExpr {
p.check_undefined_variables(names, val.right)!
}
ast.SelectorExpr {
p.check_undefined_variables(names, val.expr)!
}
ast.StringInterLiteral {
for expr_ in val.exprs {
p.check_undefined_variables(names, expr_)!
}
}
ast.StructInit {
for init_field in val.init_fields {
p.check_undefined_variables(names, init_field.expr)!
}
}
ast.UnsafeExpr {
p.check_undefined_variables(names, val.expr)!
}
else {}
}
}
fn (mut p Parser) check_cross_variables(exprs []ast.Expr, val ast.Expr) bool {
val_str := val.str()
match val {
ast.Ident {
for expr in exprs {
if expr is ast.Ident {
if expr.name == val.name {
return true
}
}
}
}
ast.IndexExpr {
for expr in exprs {
if expr.str() == val_str {
return true
}
}
}
ast.InfixExpr {
return p.check_cross_variables(exprs, val.left)
|| p.check_cross_variables(exprs, val.right)
}
ast.ParExpr {
return p.check_cross_variables(exprs, val.expr)
}
ast.CallExpr {
if p.check_cross_variables(exprs, val.left) {
return true
}
for arg in val.args {
if p.check_cross_variables(exprs, arg.expr) {
return true
}
}
}
ast.PrefixExpr {
return p.check_cross_variables(exprs, val.right)
}
ast.PostfixExpr {
return p.check_cross_variables(exprs, val.expr)
}
ast.SelectorExpr {
for expr in exprs {
if expr.str() == val_str {
return true
}
}
}
else {}
}
return false
}
fn (mut p Parser) partial_assign_stmt(left []ast.Expr, left_comments []ast.Comment) ast.Stmt {
p.is_stmt_ident = false
op := p.tok.kind
mut pos := p.tok.pos()
p.next()
mut comments := []ast.Comment{cap: 2 * left_comments.len + 1}
comments << left_comments
comments << p.eat_comments()
mut right_comments := []ast.Comment{}
mut right := []ast.Expr{cap: left.len}
right, right_comments = p.expr_list()
comments << right_comments
end_comments := p.eat_comments(same_line: true)
mut has_cross_var := false
mut is_static := false
mut is_volatile := false
for i, lx_ in left {
mut lx := unsafe { lx_ }
match mut lx {
ast.Ident {
if op == .decl_assign {
if p.scope.known_var(lx.name) {
return p.error_with_pos('redefinition of `${lx.name}`', lx.pos)
}
mut share := unsafe { ast.ShareType(0) }
if mut lx.info is ast.IdentVar {
share = lx.info.share
if lx.info.is_static {
if !p.pref.translated && !p.is_translated && !p.pref.is_fmt
&& !p.inside_unsafe_fn {
return p.error_with_pos('static variables are supported only in translated mode or in [unsafe] fn',
lx.pos)
}
is_static = true
}
if lx.info.is_volatile {
is_volatile = true
}
}
mut v := ast.Var{
name: lx.name
expr: if left.len == right.len { right[i] } else { ast.empty_expr }
share: share
is_mut: lx.is_mut || p.inside_for
pos: lx.pos
is_stack_obj: p.inside_for
}
if p.pref.autofree {
r0 := right[0]
if r0 is ast.CallExpr {
// Set correct variable position (after the or block)
// so that autofree doesn't free it in cgen before
// it's declared. (`Or` variables are declared after the or block).
if r0.or_block.pos.pos > 0 && r0.or_block.stmts.len > 0 {
v.is_or = true
// v.pos = r0.or_block.pos.
}
}
}
obj := ast.ScopeObject(v)
lx.obj = obj
p.scope.register(obj)
}
}
ast.IndexExpr {
if op == .decl_assign {
return p.error_with_pos('non-name `${lx.left}[${lx.index}]` on left side of `:=`',
lx.pos)
}
lx.is_setter = true
}
ast.ParExpr {}
ast.PrefixExpr {}
ast.SelectorExpr {
if op == .decl_assign {
return p.error_with_pos('use assignment `=` instead of declaration `:=` when modifying struct fields',
pos)
}
}
else {}
}
}
if op == .decl_assign {
// a, b := a + 1, b
for r in right {
p.check_undefined_variables(left.map(it.str()), r) or {
return p.error_with_pos(err.msg(), pos)
}
}
} else if left.len > 1 {
// a, b = b, a
for r in right {
has_cross_var = p.check_cross_variables(left, r)
if op !in [.assign, .decl_assign] {
return p.unexpected_with_pos(pos, got: op.str(), expecting: ':= or = or comma')
}
if has_cross_var {
break
}
}
}
pos.update_last_line(p.prev_tok.line_nr)
p.expr_mod = ''
return ast.AssignStmt{
op: op
left: left
right: right
comments: comments
end_comments: end_comments
pos: pos
has_cross_var: has_cross_var
is_simple: p.inside_for && p.tok.kind == .lcbr
is_static: is_static
is_volatile: is_volatile
}
}