675 lines
22 KiB
V
675 lines
22 KiB
V
// Copyright (c) 2021 Lars Pontoppidan. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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module scanner
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import os
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import math
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import toml.input
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import toml.token
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import toml.util
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pub const (
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digit_extras = [`_`, `.`, `x`, `o`, `b`, `e`, `E`]
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end_of_text = -1
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)
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// Scanner contains the necessary fields for the state of the scan process.
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// the task the scanner does is also refered to as "lexing" or "tokenizing".
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// The Scanner methods are based on much of the work in `vlib/strings/textscanner`.
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pub struct Scanner {
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pub:
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config Config
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text string // the input TOML text
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mut:
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col int // current column number (x coordinate)
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line_nr int = 1 // current line number (y coordinate)
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pos int // current flat/index position in the `text` field
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header_len int // Length, how many bytes of header was found
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// Quirks
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is_left_of_assign bool = true // indicates if the scanner is on the *left* side of an assignment
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}
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// State is a read-only copy of the scanner's internal state.
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// See also `Scanner.state()`.
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pub struct State {
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pub:
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col int // current column number (x coordinate)
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line_nr int = 1 // current line number (y coordinate)
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pos int // current flat/index position in the `text` field
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}
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// Config is used to configure a Scanner instance.
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// Only one of the fields `text` and `file_path` is allowed to be set at time of configuration.
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pub struct Config {
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pub:
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input input.Config
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tokenize_formatting bool = true // if true, generate tokens for `\n`, ` `, `\t`, `\r` etc.
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}
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// new_scanner returns a new *heap* allocated `Scanner` instance.
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pub fn new_scanner(config Config) ?&Scanner {
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config.input.validate() ?
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mut text := config.input.text
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file_path := config.input.file_path
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if os.is_file(file_path) {
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text = os.read_file(file_path) or {
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return error(@MOD + '.' + @STRUCT + '.' + @FN +
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' Could not read "$file_path": "$err.msg()"')
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}
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}
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mut s := &Scanner{
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config: config
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text: text
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}
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return s
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}
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// returns a new *stack* allocated `Scanner` instance.
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pub fn new_simple(toml_input string) ?Scanner {
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config := Config{
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input: input.auto_config(toml_input) ?
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}
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return Scanner{
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config: config
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text: config.input.read_input() ?
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}
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}
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// scan returns the next token from the input.
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[direct_array_access]
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pub fn (mut s Scanner) scan() ?token.Token {
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s.validate_and_skip_headers() ?
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for {
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c := s.next()
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byte_c := byte(c)
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if c == scanner.end_of_text {
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s.inc_line_number()
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'reached EOF')
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return s.new_token(.eof, '', 1)
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}
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ascii := byte_c.ascii_str()
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'current char "$ascii"')
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if byte_c == byte(0x0) {
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s.reset()
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return error(@MOD + '.' + @STRUCT + '.' + @FN +
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' NULL control character `$c.hex()` is not allowed at ($s.line_nr,$s.col) "$ascii" near ...${s.excerpt(s.pos, 5)}...')
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}
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is_sign := c == `+` || c == `-`
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// (+/-)nan & (+/-)inf
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peek_1 := s.peek(1)
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peek_2 := s.peek(2)
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is_nan := c == `n` && s.at() == `a` && peek_1 == `n`
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is_inf := !is_nan && c == `i` && s.at() == `n` && peek_1 == `f`
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is_signed_nan := is_sign && s.at() == `n` && peek_1 == `a` && peek_2 == `n`
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is_signed_inf := !is_signed_nan && is_sign && s.at() == `i` && peek_1 == `n`
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&& peek_2 == `f`
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if !s.is_left_of_assign && (is_nan || is_inf || is_signed_nan || is_signed_inf) {
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num := s.extract_nan_or_inf_number() ?
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified a special number "$num" ($num.len)')
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return s.new_token(.number, num, num.len)
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}
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is_signed_number := is_sign && byte(s.at()).is_digit() && !byte(s.peek(-1)).is_digit()
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is_digit := byte_c.is_digit()
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if is_digit || is_signed_number {
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num := s.extract_number() ?
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified a number "$num" ($num.len)')
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return s.new_token(.number, num, num.len)
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}
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if util.is_key_char(byte_c) {
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key := s.extract_key()
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if !s.is_left_of_assign && (key == 'true' || key == 'false') {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified a boolean "$key" ($key.len)')
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return s.new_token(.boolean, key, key.len)
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}
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified a bare key "$key" ($key.len)')
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return s.new_token(.bare, key, key.len)
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}
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match rune(c) {
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` `, `\t`, `\n`, `\r` {
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if c == `\n` {
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s.inc_line_number()
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'incremented line nr to $s.line_nr')
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}
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// Date-Time in RFC 3339 is allowed to have a space between the date and time in supplement to the 'T'
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// so we allow space characters to slip through to the parser if the space is between two digits...
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// util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, '"'+byte(s.peek(-1)).ascii_str()+'" < "$ascii" > "'+byte(s.at()).ascii_str()+'"')
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if c == ` ` && byte(s.peek(-1)).is_digit() && byte(s.at()).is_digit() {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified, what could be, a space between a RFC 3339 date and time ("$ascii") ($ascii.len)')
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return s.new_token(token.Kind.whitespace, ascii, ascii.len)
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}
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if s.config.tokenize_formatting {
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mut kind := token.Kind.whitespace
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if c == `\t` {
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kind = token.Kind.tab
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} else if c == `\r` {
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kind = token.Kind.cr
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} else if c == `\n` {
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kind = token.Kind.nl
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}
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified formatting character ("$ascii") ($ascii.len)')
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return s.new_token(kind, ascii, ascii.len)
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} else {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'skipping " ", "\\t" or "\\n" ("$ascii") ($ascii.len)')
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}
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continue
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}
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`-` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified minus "$ascii" ($ascii.len)')
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return s.new_token(.minus, ascii, ascii.len)
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}
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`_` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified underscore "$ascii" ($ascii.len)')
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return s.new_token(.underscore, ascii, ascii.len)
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}
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`+` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified plus "$ascii" ($ascii.len)')
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return s.new_token(.plus, ascii, ascii.len)
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}
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`=` {
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s.is_left_of_assign = false
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified assignment "$ascii" ($ascii.len)')
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return s.new_token(.assign, ascii, ascii.len)
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}
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`"`, `'` { // ... some string "/'
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ident_string := s.extract_string() ?
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified quoted string `$ident_string`')
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return s.new_token(.quoted, ident_string, ident_string.len)
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}
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`#` {
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hash := s.ignore_line() ?
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified comment hash "$hash" ($hash.len)')
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return s.new_token(.hash, hash, hash.len + 1)
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}
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`{` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified left curly bracket "$ascii" ($ascii.len)')
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return s.new_token(.lcbr, ascii, ascii.len)
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}
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`}` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified right curly bracket "$ascii" ($ascii.len)')
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return s.new_token(.rcbr, ascii, ascii.len)
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}
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`[` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified left square bracket "$ascii" ($ascii.len)')
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return s.new_token(.lsbr, ascii, ascii.len)
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}
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`]` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified right square bracket "$ascii" ($ascii.len)')
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return s.new_token(.rsbr, ascii, ascii.len)
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}
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`:` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified colon "$ascii" ($ascii.len)')
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return s.new_token(.colon, ascii, ascii.len)
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}
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`,` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified comma "$ascii" ($ascii.len)')
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return s.new_token(.comma, ascii, ascii.len)
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}
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`.` {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified period "$ascii" ($ascii.len)')
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return s.new_token(.period, ascii, ascii.len)
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}
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else {
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return error(@MOD + '.' + @STRUCT + '.' + @FN +
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' could not scan character `$ascii` / $c at $s.pos ($s.line_nr,$s.col) near ...${s.excerpt(s.pos, 5)}...')
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}
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}
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}
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'unknown character code at $s.pos ($s.line_nr,$s.col) near ...${s.excerpt(s.pos,
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5)}...')
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return s.new_token(.unknown, '', 0)
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}
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// free frees all allocated resources.
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[unsafe]
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pub fn (mut s Scanner) free() {
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unsafe {
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s.text.free()
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}
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}
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// remaining returns how many characters remain in the text input.
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[inline]
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pub fn (s &Scanner) remaining() int {
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return s.text.len - s.pos
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}
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// next returns the next character code from the input text.
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// next returns `end_of_text` if it can't reach the next character.
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[direct_array_access; inline]
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pub fn (mut s Scanner) next() int {
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if s.pos < s.text.len {
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opos := s.pos
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s.pos++
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s.col++
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c := s.text[opos]
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return c
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}
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return scanner.end_of_text
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}
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// skip skips one character ahead.
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[inline]
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pub fn (mut s Scanner) skip() {
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if s.pos + 1 < s.text.len {
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s.pos++
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s.col++
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}
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}
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// skip_n skips ahead `n` characters.
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// If the skip goes out of bounds from the length of `Scanner.text`,
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// the scanner position will be sat to the last character possible.
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[inline]
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pub fn (mut s Scanner) skip_n(n int) {
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s.pos += n
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if s.pos > s.text.len {
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s.pos = s.text.len
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}
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s.col = s.pos
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}
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// at returns the *current* character code from the input text.
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// at returns `end_of_text` if it can't get the current character.
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// unlike `next()`, `at()` does not change the state of the scanner.
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[direct_array_access; inline]
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pub fn (s &Scanner) at() int {
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if s.pos < s.text.len {
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return s.text[s.pos]
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}
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return scanner.end_of_text
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}
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// at_crlf returns `true` if the scanner is at a `\r` character
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// and the next character is a `\n`.
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fn (s Scanner) at_crlf() bool {
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return s.at() == `\r` && s.peek(1) == `\n`
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}
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// peek returns the character code from the input text at position + `n`.
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// peek returns `end_of_text` if it can't peek `n` characters ahead.
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[direct_array_access; inline]
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pub fn (s &Scanner) peek(n int) int {
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if s.pos + n < s.text.len {
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// Allow peeking back - needed for spaces between date and time in RFC 3339 format :/
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if n - 1 < 0 && s.pos + n - 1 >= 0 {
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// util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'LOOKING BAAAA-AACK - OOOVER MY SHOOOOULDEEEER "${s.text[s.pos + n-1]}"')
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return s.text[s.pos + n - 1]
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}
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return s.text[s.pos + n]
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}
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return scanner.end_of_text
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}
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// reset resets the internal state of the scanner.
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pub fn (mut s Scanner) reset() {
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s.pos = 0
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s.col = 0
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s.line_nr = 1
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s.header_len = 0
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}
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// new_token returns a new `token.Token`.
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[inline]
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fn (mut s Scanner) new_token(kind token.Kind, lit string, len int) token.Token {
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// println('new_token($lit)')
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mut col := s.col - len + 1
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if s.line_nr == 1 {
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col -= s.header_len
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}
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return token.Token{
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kind: kind
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lit: lit
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col: math.max(1, col)
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line_nr: s.line_nr + 1
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pos: s.pos - s.header_len - len + 1
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len: len
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}
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}
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// ignore_line forwards the scanner to the end of the current line.
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[direct_array_access; inline]
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fn (mut s Scanner) ignore_line() ?string {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, ' ignoring until EOL...')
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start := s.pos
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for c := s.at(); c != scanner.end_of_text && c != `\n`; c = s.at() {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'skipping "${byte(c).ascii_str()} / $c"')
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if s.at_crlf() {
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'letting `\\r\\n` slip through')
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break
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}
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s.next()
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}
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return s.text[start..s.pos]
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}
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// inc_line_number increases the internal line number.
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[inline]
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fn (mut s Scanner) inc_line_number() {
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s.col = 0
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s.line_nr++
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s.is_left_of_assign = true
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}
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// extract_key parses and returns a TOML key as a string.
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[direct_array_access; inline]
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fn (mut s Scanner) extract_key() string {
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s.pos--
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s.col--
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start := s.pos
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for s.pos < s.text.len {
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c := byte(s.at())
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if !(util.is_key_char(c) || c.is_digit() || c in [`_`, `-`]) {
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break
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}
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s.pos++
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s.col++
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}
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key := s.text[start..s.pos]
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return key
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}
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// extract_string collects and returns a string containing
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// any bytes recognized as a TOML string.
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// TOML strings are everything found between two double or single quotation marks (`"`/`'`).
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[direct_array_access; inline]
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fn (mut s Scanner) extract_string() ?string {
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// extract_string is called when the scanner has already reached
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// a byte that is the start of a string so we rewind it to start at the correct
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s.pos--
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s.col--
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quote := byte(s.at())
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start := s.pos
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mut lit := quote.ascii_str()
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is_multiline := s.text[s.pos + 1] == quote && s.text[s.pos + 2] == quote
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// Check for escaped multiline quote
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if is_multiline {
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mls := s.extract_multiline_string() ?
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return mls
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}
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for {
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s.pos++
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s.col++
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if s.pos >= s.text.len {
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return error(@MOD + '.' + @STRUCT + '.' + @FN +
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' unfinished single-line string literal `$quote.ascii_str()` started at $start ($s.line_nr,$s.col) "${byte(s.at()).ascii_str()}" near ...${s.excerpt(s.pos, 5)}...')
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}
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c := byte(s.at())
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util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'c: `$c.ascii_str()` / $c (quote type: $quote/$quote.ascii_str())')
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// Check for escaped chars
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if c == byte(92) {
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esc, skip := s.handle_escapes(quote, is_multiline)
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lit += esc
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if skip > 0 {
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s.pos += skip
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s.col += skip
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continue
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}
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}
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// Check for control characters (allow TAB)
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if util.is_illegal_ascii_control_character(c) {
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return error(@MOD + '.' + @STRUCT + '.' + @FN +
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' control character `$c.hex()` is not allowed at $start ($s.line_nr,$s.col) "${byte(s.at()).ascii_str()}" near ...${s.excerpt(s.pos, 5)}...')
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}
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if c == quote {
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s.pos++
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s.col++
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return lit + quote.ascii_str()
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}
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lit += c.ascii_str()
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// Don't eat multiple lines in single-line mode
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if lit.contains('\n') {
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return error(@MOD + '.' + @STRUCT + '.' + @FN +
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' unfinished single-line string literal `$quote.ascii_str()` started at $start ($s.line_nr,$s.col) "${byte(s.at()).ascii_str()}" near ...${s.excerpt(s.pos, 5)}...')
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}
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}
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return lit
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}
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// extract_multiline_string collects and returns a string containing
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// any bytes recognized as a TOML string.
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// TOML strings are everything found between two double or single quotation marks (`"`/`'`).
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[direct_array_access; inline]
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fn (mut s Scanner) extract_multiline_string() ?string {
|
|
// extract_multiline_string is called from extract_string so we know the 3 first
|
|
// characters is the quotes
|
|
quote := byte(s.at())
|
|
start := s.pos
|
|
mut lit := quote.ascii_str() + quote.ascii_str() + quote.ascii_str()
|
|
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'multi-line `$quote.ascii_str()${s.text[s.pos +
|
|
1].ascii_str()}${s.text[s.pos + 2].ascii_str()}` string started at pos $start ($s.line_nr,$s.col) (quote type: $quote.ascii_str() / $quote)')
|
|
|
|
s.pos += 2
|
|
s.col += 2
|
|
|
|
for {
|
|
s.pos++
|
|
s.col++
|
|
|
|
if s.pos >= s.text.len {
|
|
return error(@MOD + '.' + @STRUCT + '.' + @FN +
|
|
' unfinished multi-line string literal ($quote.ascii_str()$quote.ascii_str()$quote.ascii_str()) started at $start ($s.line_nr,$s.col) "${byte(s.at()).ascii_str()}" near ...${s.excerpt(s.pos, 5)}...')
|
|
}
|
|
|
|
c := byte(s.at())
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'c: `$c.ascii_str()` / $c (quote type: $quote/$quote.ascii_str())')
|
|
|
|
if c == `\n` {
|
|
s.inc_line_number()
|
|
lit += c.ascii_str()
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'c: `\\n` / $c')
|
|
continue
|
|
}
|
|
// Check for escaped chars
|
|
if c == byte(92) {
|
|
esc, skip := s.handle_escapes(quote, true)
|
|
lit += esc
|
|
if skip > 0 {
|
|
s.pos += skip
|
|
s.col += skip
|
|
continue
|
|
}
|
|
}
|
|
// Check for control characters (allow TAB)
|
|
if util.is_illegal_ascii_control_character(c) {
|
|
return error(@MOD + '.' + @STRUCT + '.' + @FN +
|
|
' control character `$c.hex()` is not allowed at $start ($s.line_nr,$s.col) "${byte(s.at()).ascii_str()}" near ...${s.excerpt(s.pos, 5)}...')
|
|
}
|
|
|
|
if c == quote {
|
|
if s.peek(1) == quote && s.peek(2) == quote {
|
|
if s.peek(3) == scanner.end_of_text {
|
|
s.pos += 3
|
|
s.col += 3
|
|
lit += quote.ascii_str() + quote.ascii_str() + quote.ascii_str()
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'returning at $c.ascii_str() `$lit`')
|
|
return lit
|
|
} else if s.peek(3) != quote {
|
|
// lit += c.ascii_str()
|
|
// lit += quote.ascii_str()
|
|
s.pos += 3
|
|
s.col += 3
|
|
lit += quote.ascii_str() + quote.ascii_str() + quote.ascii_str()
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'returning at $c.ascii_str() `$lit`')
|
|
return lit
|
|
}
|
|
}
|
|
}
|
|
lit += c.ascii_str()
|
|
}
|
|
return lit
|
|
}
|
|
|
|
// handle_escapes returns any escape character sequence.
|
|
// For escape sequence validation see `Checker.check_quoted_escapes`.
|
|
fn (mut s Scanner) handle_escapes(quote byte, is_multiline bool) (string, int) {
|
|
c := byte(s.at())
|
|
mut lit := c.ascii_str()
|
|
is_literal_string := quote == `'`
|
|
if !is_literal_string {
|
|
if s.peek(1) == `u` && byte(s.peek(2)).is_hex_digit() && byte(s.peek(3)).is_hex_digit()
|
|
&& byte(s.peek(4)).is_hex_digit() && byte(s.peek(5)).is_hex_digit() {
|
|
lit += s.text[s.pos + 1..s.pos + 6] //.ascii_str()
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'gulp escaped unicode `$lit`')
|
|
return lit, 5
|
|
} else if s.peek(1) == quote {
|
|
if (!is_multiline && s.peek(2) == `\n`)
|
|
|| (is_multiline && s.peek(2) == quote && s.peek(3) == quote && s.peek(4) == `\n`) {
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'ignore special case escaped `$lit` at end of string')
|
|
return '', 0
|
|
}
|
|
lit += quote.ascii_str()
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'gulp escaped `$lit`')
|
|
return lit, 1
|
|
}
|
|
}
|
|
if is_literal_string {
|
|
if s.peek(1) == quote {
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'ignore escape `$lit${byte(s.peek(1)).ascii_str()}` in literal string')
|
|
return '', 0
|
|
}
|
|
}
|
|
|
|
lit += byte(s.peek(1)).ascii_str()
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'gulp escaped `$lit`')
|
|
return lit, 1
|
|
}
|
|
|
|
// extract_number collects and returns a string containing
|
|
// any bytes recognized as a TOML number except for "(+/-)nan" and "(+/-)inf".
|
|
// TOML numbers can include digits 0-9 and `_`.
|
|
[direct_array_access; inline]
|
|
fn (mut s Scanner) extract_number() ?string {
|
|
// extract_number is called when the scanner has already reached
|
|
// a byte that is a number or +/- - so we rewind it to start at the correct
|
|
// position to get the complete number. Even if it's only one digit
|
|
s.pos--
|
|
s.col--
|
|
start := s.pos
|
|
|
|
mut c := s.at()
|
|
is_digit := byte(c).is_digit()
|
|
if !(is_digit || c in [`+`, `-`]) {
|
|
return error(@MOD + '.' + @STRUCT + '.' + @FN +
|
|
' ${byte(c).ascii_str()} is not a number at ${s.excerpt(s.pos, 10)}')
|
|
}
|
|
s.pos++
|
|
s.col++
|
|
for s.pos < s.text.len {
|
|
c = s.at()
|
|
// Handle signed exponent notation. I.e.: 3e2, 3E2, 3e-2, 3E+2, 3e0, 3.1e2, 3.1E2, -1E-1
|
|
if c in [`e`, `E`] && s.peek(1) in [`+`, `-`] && byte(s.peek(2)).is_digit() {
|
|
s.pos += 2
|
|
s.col += 2
|
|
}
|
|
c = s.at()
|
|
if !(byte(c).is_hex_digit() || c in scanner.digit_extras)
|
|
|| (c == `.` && s.is_left_of_assign) {
|
|
break
|
|
}
|
|
s.pos++
|
|
s.col++
|
|
}
|
|
key := s.text[start..s.pos]
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified number "$key" in range [$start .. $s.pos]')
|
|
return key
|
|
}
|
|
|
|
// extract_nan_or_inf_number collects and returns a string containing
|
|
// any bytes recognized as infinity or not-a-number TOML numbers.
|
|
[direct_array_access; inline]
|
|
fn (mut s Scanner) extract_nan_or_inf_number() ?string {
|
|
// extract_nan_or_inf_number is called when the scanner has already identified that
|
|
// +/- or 'nan'/'inf' bytes is up but we rewind it to start at the correct position
|
|
s.pos--
|
|
s.col--
|
|
start := s.pos
|
|
|
|
mut c := s.at()
|
|
if c !in [`+`, `-`, `n`, `i`] {
|
|
return error(@MOD + '.' + @STRUCT + '.' + @FN +
|
|
' ${byte(c).ascii_str()} is not a number at ${s.excerpt(s.pos, 10)}')
|
|
}
|
|
s.pos++
|
|
s.col++
|
|
for s.pos < s.text.len {
|
|
c = s.at()
|
|
if c !in [`n`, `a`, `i`, `f`] {
|
|
break
|
|
}
|
|
s.pos++
|
|
s.col++
|
|
}
|
|
key := s.text[start..s.pos]
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'identified special number "$key" in range [$start .. $s.pos]')
|
|
return key
|
|
}
|
|
|
|
// excerpt returns a string excerpt of the input text centered
|
|
// at `pos`. The `margin` argument defines how many chacters
|
|
// on each side of `pos` is returned
|
|
pub fn (s Scanner) excerpt(pos int, margin int) string {
|
|
start := if pos > 0 && pos >= margin { pos - margin } else { 0 }
|
|
end := if pos + margin < s.text.len { pos + margin } else { s.text.len }
|
|
return s.text[start..end].replace('\n', r'\n')
|
|
}
|
|
|
|
// state returns a read-only view of the scanner's internal state.
|
|
pub fn (s Scanner) state() State {
|
|
return State{
|
|
col: s.col
|
|
line_nr: s.line_nr
|
|
pos: s.pos
|
|
}
|
|
}
|
|
|
|
fn (mut s Scanner) validate_and_skip_headers() ? {
|
|
// UTF-16 / UTF-32 headers (BE/LE)
|
|
s.check_utf16_or_32_bom() ?
|
|
|
|
// NICE-TO-HAVE-TODO Check other types of (UTF-?) headers and yield an error. TOML is UTF-8 only.
|
|
|
|
// Skip optional UTF-8 heaser, if any.
|
|
if s.at() == 0xEF && s.peek(1) == 0xBB && s.peek(2) == 0xBF {
|
|
util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'skipping UTF-8 byte order mark (BOM)')
|
|
s.header_len = 3
|
|
s.skip_n(s.header_len)
|
|
}
|
|
|
|
// Check after we've skipped UTF-8 BOM
|
|
s.check_utf16_or_32_bom() ?
|
|
}
|
|
|
|
fn (mut s Scanner) check_utf16_or_32_bom() ? {
|
|
if (s.at() == 0xFF && s.peek(1) == 0xFE && s.peek(2) == 0x00 && s.peek(3) == 0x00)
|
|
|| (s.at() == 0x00 && s.peek(1) == 0x00 && s.peek(2) == 0xFE && s.peek(3) == 0xFF) {
|
|
s.header_len = 4
|
|
s.skip_n(s.header_len)
|
|
return error(@MOD + '.' + @STRUCT + '.' + @FN +
|
|
' UTF-32 is not a valid TOML encoding at $s.pos ($s.line_nr,$s.col) near ...${s.excerpt(s.pos, 5)}...')
|
|
}
|
|
if (s.at() == 0xFE && s.peek(1) == 0xFF) || (s.at() == 0xFF && s.peek(1) == 0xFE) {
|
|
s.header_len = 2
|
|
s.skip_n(s.header_len)
|
|
return error(@MOD + '.' + @STRUCT + '.' + @FN +
|
|
' UTF-16 is not a valid TOML encoding at $s.pos ($s.line_nr,$s.col) near ...${s.excerpt(s.pos, 5)}...')
|
|
}
|
|
}
|