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compiler: multiple return - allow mut decl & disallow assignment with deceleration (#2251)
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joe-conigliaro
GitHub
parent
ac5241b5bd
commit
8fea5170be
@ -1426,27 +1426,31 @@ fn (p mut Parser) var_decl() {
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p.fspace()
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}
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mut names := []string
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mut vtoken_idxs := []int
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mut var_token_idxs := [p.cur_tok_index()]
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mut var_mut := [is_mut] // add first var mut
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mut var_names := [p.check_name()] // add first variable
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vtoken_idxs << p.cur_tok_index()
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// first variable
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names << p.check_name()
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p.scanner.validate_var_name(names[0])
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mut new_vars := 0
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if names[0] != '_' && !p.known_var(names[0]) {
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new_vars++
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}
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p.scanner.validate_var_name(var_names[0])
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// mut new_vars := 0
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// if var_names[0] != '_' && !p.known_var(var_names[0]) {
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// new_vars++
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// }
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// more than 1 vars (multiple returns)
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for p.tok == .comma {
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p.check(.comma)
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vtoken_idxs << p.cur_tok_index()
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name := p.check_name()
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names << name
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p.scanner.validate_var_name(name)
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if name != '_' && !p.known_var(name) {
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new_vars++
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if p.tok == .key_mut {
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p.check(.key_mut)
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var_mut << true
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} else {
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var_mut << false
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}
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var_token_idxs << p.cur_tok_index()
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var_name := p.check_name()
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p.scanner.validate_var_name(var_name)
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// if var_name != '_' && !p.known_var(var_name) {
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// new_vars++
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// }
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var_names << var_name
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}
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is_assign := p.tok == .assign
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is_decl_assign := p.tok == .decl_assign
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@ -1458,72 +1462,78 @@ fn (p mut Parser) var_decl() {
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p.error('expected `=` or `:=`')
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}
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// all vars on left of `:=` already defined
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if is_decl_assign && names.len > 1 && new_vars == 0 {
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p.error('no new variables on left side of `:=`')
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}
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p.var_decl_name = if names.len > 1 { '__ret_'+names.join('_') } else { names[0] }
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// if is_decl_assign && var_names.len > 1 && new_vars == 0 {
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// p.error_with_token_index('no new variables on left side of `:=`', var_token_idxs.last())
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// }
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p.var_decl_name = if var_names.len > 1 { '_V_mret_'+var_names.join('_') } else { var_names[0] }
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t := p.gen_var_decl(p.var_decl_name, is_static)
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mut types := [t]
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mut var_types := [t]
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// multiple returns types
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if names.len > 1 {
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// should we register __ret var?
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types = t.replace('_V_MulRet_', '').replace('_PTR_', '*').split('_V_')
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}
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for i, name in names {
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var_token_idx := vtoken_idxs[i]
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if name == '_' {
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continue
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}
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typ := types[i]
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// println('var decl tok=${p.strtok()} ismut=$is_mut')
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// Don't allow declaring a variable with the same name. Even in a child scope
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// (shadowing is not allowed)
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known_var := p.known_var(name)
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// single var decl, already exists
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if names.len == 1 && !p.builtin_mod && known_var {
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p.error_with_token_index('redefinition of `$name`', var_token_idx)
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}
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// assignment, but var does not exist
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if names.len > 1 && is_assign && !known_var {
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suggested := p.find_misspelled_local_var(name, 50)
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if suggested != '' {
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p.error_with_token_index('undefined: `$name`. did you mean:$suggested', var_token_idx)
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}
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p.error_with_token_index('undefined: `$name`.', var_token_idx)
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}
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if name.len > 1 && contains_capital(name) {
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p.error_with_token_index('variable names cannot contain uppercase letters, use snake_case instead', var_token_idx)
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if var_names.len > 1 {
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var_types = t.replace('_V_MulRet_', '').replace('_PTR_', '*').split('_V_')
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}
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// mismatched number of return & assignment vars
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if names.len != types.len {
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if var_names.len != var_types.len {
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mr_fn := p.cgen.cur_line.find_between('=', '(').trim_space()
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p.error_with_token_index('assignment mismatch: ${names.len} variables but `$mr_fn` returns $types.len values', var_token_idx)
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p.error_with_token_index('assignment mismatch: ${var_names.len} variables but `$mr_fn` returns $var_types.len values', var_token_idxs.last())
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}
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for i, var_name in var_names {
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var_token_idx := var_token_idxs[i]
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if var_name == '_' {
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continue
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}
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var_is_mut := var_mut[i]
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var_type := var_types[i]
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known_var := p.known_var(var_name)
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// println('var decl tok=${p.strtok()} name=type=$var_name type=$var_type ismut=$var_is_mut')
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// var decl, already exists (shadowing is not allowed)
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// Don't allow declaring a variable with the same name. Even in a child scope
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// if var_names.len == 1 && !p.builtin_mod && known_var {
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if is_decl_assign && known_var {
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p.error_with_token_index('redefinition of `$var_name`', var_token_idx)
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}
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// mut specified with assignment
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if /*is_assign && implicit*/ known_var && var_is_mut {
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p.error_with_token_index('cannot specify mutability for existing var `$var_name`, only for new vars', var_token_idx)
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}
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// assignment, but var does not exist
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if is_assign && !known_var {
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suggested := p.find_misspelled_local_var(var_name, 50)
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if suggested != '' {
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p.error_with_token_index('undefined: `$var_name`. did you mean:$suggested', var_token_idx)
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}
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p.error_with_token_index('undefined: `$var_name`.', var_token_idx)
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}
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if var_name.len > 1 && contains_capital(var_name) {
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p.error_with_token_index('variable names cannot contain uppercase letters, use snake_case instead', var_token_idx)
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}
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// multiple return
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if names.len > 1 {
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if var_names.len > 1 {
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p.gen(';\n')
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// assigment
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if !p.builtin_mod && known_var {
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v := p.find_var(name) or {
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p.error_with_token_index('cannot find `$name`', var_token_idx)
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// if !p.builtin_mod && known_var {
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if known_var {
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v := p.find_var(var_name) or {
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p.error_with_token_index('cannot find `$var_name`', var_token_idx)
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break
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}
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p.check_types_with_token_index(typ, v.typ, var_token_idx)
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p.check_types_with_token_index(var_type, v.typ, var_token_idx)
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if !v.is_mut {
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p.error_with_token_index('`$v.name` is immutable', var_token_idx)
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}
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p.mark_var_used(v)
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p.mark_var_changed(v)
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p.gen('$name = ${p.var_decl_name}.var_$i')
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p.gen('$var_name = ${p.var_decl_name}.var_$i')
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continue
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}
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// decleration
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p.gen('$typ $name = ${p.var_decl_name}.var_$i')
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p.gen('$var_type $var_name = ${p.var_decl_name}.var_$i')
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}
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p.register_var(Var {
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name: name
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typ: typ
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is_mut: is_mut
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is_alloc: p.is_alloc || typ.starts_with('array_')
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name: var_name
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typ: var_type
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is_mut: var_is_mut
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is_alloc: p.is_alloc || var_type.starts_with('array_')
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line_nr: p.tokens[ var_token_idx ].line_nr
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token_idx: var_token_idx
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})
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