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parser: multiple returns, allow assignment as well as deceleration closes

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joe-conigliaro 2019-10-06 03:17:09 +11:00 committed by Alexander Medvednikov
parent 735336e569
commit 22f162c3cd
2 changed files with 69 additions and 23 deletions
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86
compiler/parser.v
View File

@ -1419,20 +1419,41 @@ fn (p mut Parser) var_decl() {
mut vtoken_idxs := []int
vtoken_idxs << p.cur_tok_index()
// first variable
names << p.check_name()
p.scanner.validate_var_name(names[0])
mut new_vars := 0
if names[0] != '_' && !p.known_var(names[0]) {
new_vars++
}
// more than 1 vars (multiple returns)
for p.tok == .comma {
p.check(.comma)
vtoken_idxs << p.cur_tok_index()
names << p.check_name()
name := p.check_name()
names << name
p.scanner.validate_var_name(name)
if name != '_' && !p.known_var(name) {
new_vars++
}
}
mr_var_name := if names.len > 1 { '__ret_'+names.join('_') } else { names[0] }
p.check_space(.decl_assign) // :=
// t := p.bool_expression()
p.var_decl_name = mr_var_name
t := p.gen_var_decl(mr_var_name, is_static)
is_assign := p.tok == .assign
is_decl_assign := p.tok == .decl_assign
if is_assign {
p.check_space(.assign) // =
} else if is_decl_assign {
p.check_space(.decl_assign) // :=
} else {
p.error('expected `=` or `:=`')
}
// all vars on left of `:=` already defined
if is_decl_assign && names.len > 1 && new_vars == 0 {
p.error('no new variables on left side of `:=`')
}
p.var_decl_name = if names.len > 1 { '__ret_'+names.join('_') } else { names[0] }
t := p.gen_var_decl(p.var_decl_name, is_static)
mut types := [t]
// multiple returns
// multiple returns types
if names.len > 1 {
// should we register __ret var?
types = t.replace('_V_MulRet_', '').replace('_PTR_', '*').split('_V_')
@ -1440,34 +1461,53 @@ fn (p mut Parser) var_decl() {
for i, name in names {
var_token_idx := vtoken_idxs[i]
if name == '_' {
if names.len == 1 {
p.error_with_token_index('no new variables on left side of `:=`', var_token_idx)
}
continue
}
typ := types[i]
// println('var decl tok=${p.strtok()} ismut=$is_mut')
// name := p.check_name()
// p.var_decl_name = name
// Don't allow declaring a variable with the same name. Even in a child scope
// (shadowing is not allowed)
if !p.builtin_mod && p.known_var(name) {
// v := p.cur_fn.find_var(name)
known_var := p.known_var(name)
// single var decl, already exists
if names.len == 1 && !p.builtin_mod && known_var {
p.error_with_token_index('redefinition of `$name`', var_token_idx)
}
// assignment, but var does not exist
if names.len > 1 && is_assign && !known_var {
suggested := p.find_misspelled_local_var(name, 50)
if suggested != '' {
p.error_with_token_index('undefined: `$name`. did you mean:$suggested', var_token_idx)
}
p.error_with_token_index('undefined: `$name`.', var_token_idx)
}
if name.len > 1 && contains_capital(name) {
p.error_with_token_index('variable names cannot contain uppercase letters, use snake_case instead', var_token_idx)
}
if names.len > 1 {
if names.len != types.len {
mr_fn := p.cgen.cur_line.find_between('=', '(').trim_space()
p.error_with_token_index('assignment mismatch: ${names.len} variables but `$mr_fn` returns $types.len values', var_token_idx)
}
p.gen(';\n')
p.gen('$typ $name = ${mr_var_name}.var_$i')
// mismatched number of return & assignment vars
if names.len != types.len {
mr_fn := p.cgen.cur_line.find_between('=', '(').trim_space()
p.error_with_token_index('assignment mismatch: ${names.len} variables but `$mr_fn` returns $types.len values', var_token_idx)
}
// multiple return
if names.len > 1 {
p.gen(';\n')
// assigment
if !p.builtin_mod && known_var {
v := p.find_var(name) or {
p.error_with_token_index('cannot find `$name`', var_token_idx)
break
}
p.check_types_with_token_index(typ, v.typ, var_token_idx)
if !v.is_mut {
p.error_with_token_index('`$v.name` is immutable', var_token_idx)
}
p.mark_var_changed(v)
p.gen('$name = ${p.var_decl_name}.var_$i')
continue
}
// decleration
p.gen('$typ $name = ${p.var_decl_name}.var_$i')
}
// p.check_space(.decl_assign) // :=
// typ := p.gen_var_decl(name, is_static)
p.register_var(Var {
name: name
typ: typ

6
compiler/table.v
View File

@ -689,6 +689,12 @@ fn (p mut Parser) check_types_no_throw(got, expected string) bool {
return p._check_types(got, expected, false)
}
fn (p mut Parser) check_types_with_token_index(got, expected string, var_token_idx int) {
if !p._check_types(got, expected, false) {
p.error_with_token_index('expected type `$expected`, but got `$got`', var_token_idx)
}
}
fn (p mut Parser) satisfies_interface(interface_name, _typ string, throw bool) bool {
int_typ := p.table.find_type(interface_name)
typ := p.table.find_type(_typ)