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Diffstat (limited to 'vendor/github.com/jesseduffield/yaml/scannerc.go')
| -rw-r--r-- | vendor/github.com/jesseduffield/yaml/scannerc.go | 2702 |
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diff --git a/vendor/github.com/jesseduffield/yaml/scannerc.go b/vendor/github.com/jesseduffield/yaml/scannerc.go new file mode 100644 index 000000000..492a9845d --- /dev/null +++ b/vendor/github.com/jesseduffield/yaml/scannerc.go @@ -0,0 +1,2702 @@ +package yaml + +import ( + "bytes" + "fmt" +) + +// Introduction +// ************ +// +// The following notes assume that you are familiar with the YAML specification +// (http://yaml.org/spec/1.2/spec.html). We mostly follow it, although in +// some cases we are less restrictive that it requires. +// +// The process of transforming a YAML stream into a sequence of events is +// divided on two steps: Scanning and Parsing. +// +// The Scanner transforms the input stream into a sequence of tokens, while the +// parser transform the sequence of tokens produced by the Scanner into a +// sequence of parsing events. +// +// The Scanner is rather clever and complicated. The Parser, on the contrary, +// is a straightforward implementation of a recursive-descendant parser (or, +// LL(1) parser, as it is usually called). +// +// Actually there are two issues of Scanning that might be called "clever", the +// rest is quite straightforward. The issues are "block collection start" and +// "simple keys". Both issues are explained below in details. +// +// Here the Scanning step is explained and implemented. We start with the list +// of all the tokens produced by the Scanner together with short descriptions. +// +// Now, tokens: +// +// STREAM-START(encoding) # The stream start. +// STREAM-END # The stream end. +// VERSION-DIRECTIVE(major,minor) # The '%YAML' directive. +// TAG-DIRECTIVE(handle,prefix) # The '%TAG' directive. +// DOCUMENT-START # '---' +// DOCUMENT-END # '...' +// BLOCK-SEQUENCE-START # Indentation increase denoting a block +// BLOCK-MAPPING-START # sequence or a block mapping. +// BLOCK-END # Indentation decrease. +// FLOW-SEQUENCE-START # '[' +// FLOW-SEQUENCE-END # ']' +// BLOCK-SEQUENCE-START # '{' +// BLOCK-SEQUENCE-END # '}' +// BLOCK-ENTRY # '-' +// FLOW-ENTRY # ',' +// KEY # '?' or nothing (simple keys). +// VALUE # ':' +// ALIAS(anchor) # '*anchor' +// ANCHOR(anchor) # '&anchor' +// TAG(handle,suffix) # '!handle!suffix' +// SCALAR(value,style) # A scalar. +// +// The following two tokens are "virtual" tokens denoting the beginning and the +// end of the stream: +// +// STREAM-START(encoding) +// STREAM-END +// +// We pass the information about the input stream encoding with the +// STREAM-START token. +// +// The next two tokens are responsible for tags: +// +// VERSION-DIRECTIVE(major,minor) +// TAG-DIRECTIVE(handle,prefix) +// +// Example: +// +// %YAML 1.1 +// %TAG ! !foo +// %TAG !yaml! tag:yaml.org,2002: +// --- +// +// The correspoding sequence of tokens: +// +// STREAM-START(utf-8) +// VERSION-DIRECTIVE(1,1) +// TAG-DIRECTIVE("!","!foo") +// TAG-DIRECTIVE("!yaml","tag:yaml.org,2002:") +// DOCUMENT-START +// STREAM-END +// +// Note that the VERSION-DIRECTIVE and TAG-DIRECTIVE tokens occupy a whole +// line. +// +// The document start and end indicators are represented by: +// +// DOCUMENT-START +// DOCUMENT-END +// +// Note that if a YAML stream contains an implicit document (without '---' +// and '...' indicators), no DOCUMENT-START and DOCUMENT-END tokens will be +// produced. +// +// In the following examples, we present whole documents together with the +// produced tokens. +// +// 1. An implicit document: +// +// 'a scalar' +// +// Tokens: +// +// STREAM-START(utf-8) +// SCALAR("a scalar",single-quoted) +// STREAM-END +// +// 2. An explicit document: +// +// --- +// 'a scalar' +// ... +// +// Tokens: +// +// STREAM-START(utf-8) +// DOCUMENT-START +// SCALAR("a scalar",single-quoted) +// DOCUMENT-END +// STREAM-END +// +// 3. Several documents in a stream: +// +// 'a scalar' +// --- +// 'another scalar' +// --- +// 'yet another scalar' +// +// Tokens: +// +// STREAM-START(utf-8) +// SCALAR("a scalar",single-quoted) +// DOCUMENT-START +// SCALAR("another scalar",single-quoted) +// DOCUMENT-START +// SCALAR("yet another scalar",single-quoted) +// STREAM-END +// +// We have already introduced the SCALAR token above. The following tokens are +// used to describe aliases, anchors, tag, and scalars: +// +// ALIAS(anchor) +// ANCHOR(anchor) +// TAG(handle,suffix) +// SCALAR(value,style) +// +// The following series of examples illustrate the usage of these tokens: +// +// 1. A recursive sequence: +// +// &A [ *A ] +// +// Tokens: +// +// STREAM-START(utf-8) +// ANCHOR("A") +// FLOW-SEQUENCE-START +// ALIAS("A") +// FLOW-SEQUENCE-END +// STREAM-END +// +// 2. A tagged scalar: +// +// !!float "3.14" # A good approximation. +// +// Tokens: +// +// STREAM-START(utf-8) +// TAG("!!","float") +// SCALAR("3.14",double-quoted) +// STREAM-END +// +// 3. Various scalar styles: +// +// --- # Implicit empty plain scalars do not produce tokens. +// --- a plain scalar +// --- 'a single-quoted scalar' +// --- "a double-quoted scalar" +// --- |- +// a literal scalar +// --- >- +// a folded +// scalar +// +// Tokens: +// +// STREAM-START(utf-8) +// DOCUMENT-START +// DOCUMENT-START +// SCALAR("a plain scalar",plain) +// DOCUMENT-START +// SCALAR("a single-quoted scalar",single-quoted) +// DOCUMENT-START +// SCALAR("a double-quoted scalar",double-quoted) +// DOCUMENT-START +// SCALAR("a literal scalar",literal) +// DOCUMENT-START +// SCALAR("a folded scalar",folded) +// STREAM-END +// +// Now it's time to review collection-related tokens. We will start with +// flow collections: +// +// FLOW-SEQUENCE-START +// FLOW-SEQUENCE-END +// FLOW-MAPPING-START +// FLOW-MAPPING-END +// FLOW-ENTRY +// KEY +// VALUE +// +// The tokens FLOW-SEQUENCE-START, FLOW-SEQUENCE-END, FLOW-MAPPING-START, and +// FLOW-MAPPING-END represent the indicators '[', ']', '{', and '}' +// correspondingly. FLOW-ENTRY represent the ',' indicator. Finally the +// indicators '?' and ':', which are used for denoting mapping keys and values, +// are represented by the KEY and VALUE tokens. +// +// The following examples show flow collections: +// +// 1. A flow sequence: +// +// [item 1, item 2, item 3] +// +// Tokens: +// +// STREAM-START(utf-8) +// FLOW-SEQUENCE-START +// SCALAR("item 1",plain) +// FLOW-ENTRY +// SCALAR("item 2",plain) +// FLOW-ENTRY +// SCALAR("item 3",plain) +// FLOW-SEQUENCE-END +// STREAM-END +// +// 2. A flow mapping: +// +// { +// a simple key: a value, # Note that the KEY token is produced. +// ? a complex key: another value, +// } +// +// Tokens: +// +// STREAM-START(utf-8) +// FLOW-MAPPING-START +// KEY +// SCALAR("a simple key",plain) +// VALUE +// SCALAR("a value",plain) +// FLOW-ENTRY +// KEY +// SCALAR("a complex key",plain) +// VALUE +// SCALAR("another value",plain) +// FLOW-ENTRY +// FLOW-MAPPING-END +// STREAM-END +// +// A simple key is a key which is not denoted by the '?' indicator. Note that +// the Scanner still produce the KEY token whenever it encounters a simple key. +// +// For scanning block collections, the following tokens are used (note that we +// repeat KEY and VALUE here): +// +// BLOCK-SEQUENCE-START +// BLOCK-MAPPING-START +// BLOCK-END +// BLOCK-ENTRY +// KEY +// VALUE +// +// The tokens BLOCK-SEQUENCE-START and BLOCK-MAPPING-START denote indentation +// increase that precedes a block collection (cf. the INDENT token in Python). +// The token BLOCK-END denote indentation decrease that ends a block collection +// (cf. the DEDENT token in Python). However YAML has some syntax pecularities +// that makes detections of these tokens more complex. +// +// The tokens BLOCK-ENTRY, KEY, and VALUE are used to represent the indicators +// '-', '?', and ':' correspondingly. +// +// The following examples show how the tokens BLOCK-SEQUENCE-START, +// BLOCK-MAPPING-START, and BLOCK-END are emitted by the Scanner: +// +// 1. Block sequences: +// +// - item 1 +// - item 2 +// - +// - item 3.1 +// - item 3.2 +// - +// key 1: value 1 +// key 2: value 2 +// +// Tokens: +// +// STREAM-START(utf-8) +// BLOCK-SEQUENCE-START +// BLOCK-ENTRY +// SCALAR("item 1",plain) +// BLOCK-ENTRY +// SCALAR("item 2",plain) +// BLOCK-ENTRY +// BLOCK-SEQUENCE-START +// BLOCK-ENTRY +// SCALAR("item 3.1",plain) +// BLOCK-ENTRY +// SCALAR("item 3.2",plain) +// BLOCK-END +// BLOCK-ENTRY +// BLOCK-MAPPING-START +// KEY +// SCALAR("key 1",plain) +// VALUE +// SCALAR("value 1",plain) +// KEY +// SCALAR("key 2",plain) +// VALUE +// SCALAR("value 2",plain) +// BLOCK-END +// BLOCK-END +// STREAM-END +// +// 2. Block mappings: +// +// a simple key: a value # The KEY token is produced here. +// ? a complex key +// : another value +// a mapping: +// key 1: value 1 +// key 2: value 2 +// a sequence: +// - item 1 +// - item 2 +// +// Tokens: +// +// STREAM-START(utf-8) +// BLOCK-MAPPING-START +// KEY +// SCALAR("a simple key",plain) +// VALUE +// SCALAR("a value",plain) +// KEY +// SCALAR("a complex key",plain) +// VALUE +// SCALAR("another value",plain) +// KEY +// SCALAR("a mapping",plain) +// BLOCK-MAPPING-START +// KEY +// SCALAR("key 1",plain) +// VALUE +// SCALAR("value 1",plain) +// KEY +// SCALAR("key 2",plain) +// VALUE +// SCALAR("value 2",plain) +// BLOCK-END +// KEY +// SCALAR("a sequence",plain) +// VALUE +// BLOCK-SEQUENCE-START +// BLOCK-ENTRY +// SCALAR("item 1",plain) +// BLOCK-ENTRY +// SCALAR("item 2",plain) +// BLOCK-END +// BLOCK-END +// STREAM-END +// +// YAML does not always require to start a new block collection from a new +// line. If the current line contains only '-', '?', and ':' indicators, a new +// block collection may start at the current line. The following examples +// illustrate this case: +// +// 1. Collections in a sequence: +// +// - - item 1 +// - item 2 +// - key 1: value 1 +// key 2: value 2 +// - ? complex key +// : complex value +// +// Tokens: +// +// STREAM-START(utf-8) +// BLOCK-SEQUENCE-START +// BLOCK-ENTRY +// BLOCK-SEQUENCE-START +// BLOCK-ENTRY +// SCALAR("item 1",plain) +// BLOCK-ENTRY +// SCALAR("item 2",plain) +// BLOCK-END +// BLOCK-ENTRY +// BLOCK-MAPPING-START +// KEY +// SCALAR("key 1",plain) +// VALUE +// SCALAR("value 1",plain) +// KEY +// SCALAR("key 2",plain) +// VALUE +// SCALAR("value 2",plain) +// BLOCK-END +// BLOCK-ENTRY +// BLOCK-MAPPING-START +// KEY +// SCALAR("complex key") +// VALUE +// SCALAR("complex value") +// BLOCK-END +// BLOCK-END +// STREAM-END +// +// 2. Collections in a mapping: +// +// ? a sequence +// : - item 1 +// - item 2 +// ? a mapping +// : key 1: value 1 +// key 2: value 2 +// +// Tokens: +// +// STREAM-START(utf-8) +// BLOCK-MAPPING-START +// KEY +// SCALAR("a sequence",plain) +// VALUE +// BLOCK-SEQUENCE-START +// BLOCK-ENTRY +// SCALAR("item 1",plain) +// BLOCK-ENTRY +// SCALAR("item 2",plain) +// BLOCK-END +// KEY +// SCALAR("a mapping",plain) +// VALUE +// BLOCK-MAPPING-START +// KEY +// SCALAR("key 1",plain) +// VALUE +// SCALAR("value 1",plain) +// KEY +// SCALAR("key 2",plain) +// VALUE +// SCALAR("value 2",plain) +// BLOCK-END +// BLOCK-END +// STREAM-END +// +// YAML also permits non-indented sequences if they are included into a block +// mapping. In this case, the token BLOCK-SEQUENCE-START is not produced: +// +// key: +// - item 1 # BLOCK-SEQUENCE-START is NOT produced here. +// - item 2 +// +// Tokens: +// +// STREAM-START(utf-8) +// BLOCK-MAPPING-START +// KEY +// SCALAR("key",plain) +// VALUE +// BLOCK-ENTRY +// SCALAR("item 1",plain) +// BLOCK-ENTRY +// SCALAR("item 2",plain) +// BLOCK-END +// + +// Ensure that the buffer contains the required number of characters. +// Return true on success, false on failure (reader error or memory error). +func cache(parser *yaml_parser_t, length int) bool { + // [Go] This was inlined: !cache(A, B) -> unread < B && !update(A, B) + return parser.unread >= length || yaml_parser_update_buffer(parser, length) +} + +// Advance the buffer pointer. +func skip(parser *yaml_parser_t) { + parser.mark.index++ + parser.mark.column++ + parser.unread-- + parser.buffer_pos += width(parser.buffer[parser.buffer_pos]) +} + +func skip_line(parser *yaml_parser_t) { + if is_crlf(parser.buffer, parser.buffer_pos) { + parser.mark.index += 2 + parser.mark.column = 0 + parser.mark.line++ + parser.unread -= 2 + parser.buffer_pos += 2 + } else if is_break(parser.buffer, parser.buffer_pos) { + parser.mark.index++ + parser.mark.column = 0 + parser.mark.line++ + parser.unread-- + parser.buffer_pos += width(parser.buffer[parser.buffer_pos]) + } +} + +// Copy a character to a string buffer and advance pointers. +func read(parser *yaml_parser_t, s []byte) []byte { + w := width(parser.buffer[parser.buffer_pos]) + if w == 0 { + panic("invalid character sequence") + } + if len(s) == 0 { + s = make([]byte, 0, 32) + } + if w == 1 && len(s)+w <= cap(s) { + s = s[:len(s)+1] + s[len(s)-1] = parser.buffer[parser.buffer_pos] + parser.buffer_pos++ + } else { + s = append(s, parser.buffer[parser.buffer_pos:parser.buffer_pos+w]...) + parser.buffer_pos += w + } + parser.mark.index++ + parser.mark.column++ + parser.unread-- + return s +} + +// Copy a line break character to a string buffer and advance pointers. +func read_line(parser *yaml_parser_t, s []byte) []byte { + buf := parser.buffer + pos := parser.buffer_pos + switch { + case buf[pos] == '\r' && buf[pos+1] == '\n': + // CR LF . LF + s = append(s, '\n') + parser.buffer_pos += 2 + parser.mark.index++ + parser.unread-- + case buf[pos] == '\r' || buf[pos] == '\n': + // CR|LF . LF + s = append(s, '\n') + parser.buffer_pos += 1 + case buf[pos] == '\xC2' && buf[pos+1] == '\x85': + // NEL . LF + s = append(s, '\n') + parser.buffer_pos += 2 + case buf[pos] == '\xE2' && buf[pos+1] == '\x80' && (buf[pos+2] == '\xA8' || buf[pos+2] == '\xA9'): + // LS|PS . LS|PS + s = append(s, buf[parser.buffer_pos:pos+3]...) + parser.buffer_pos += 3 + default: + return s + } + parser.mark.index++ + parser.mark.column = 0 + parser.mark.line++ + parser.unread-- + return s +} + +// Get the next token. +func yaml_parser_scan(parser *yaml_parser_t, token *yaml_token_t) bool { + // Erase the token object. + *token = yaml_token_t{} // [Go] Is this necessary? + + // No tokens after STREAM-END or error. + if parser.stream_end_produced || parser.error != yaml_NO_ERROR { + return true + } + + // Ensure that the tokens queue contains enough tokens. + if !parser.token_available { + if !yaml_parser_fetch_more_tokens(parser) { + return false + } + } + + // Fetch the next token from the queue. + *token = parser.tokens[parser.tokens_head] + parser.tokens_head++ + parser.tokens_parsed++ + parser.token_available = false + + if token.typ == yaml_STREAM_END_TOKEN { + parser.stream_end_produced = true + } + return true +} + +// Set the scanner error and return false. +func yaml_parser_set_scanner_error(parser *yaml_parser_t, context string, context_mark yaml_mark_t, problem string) bool { + parser.error = yaml_SCANNER_ERROR + parser.context = context + parser.context_mark = context_mark + parser.problem = problem + parser.problem_mark = parser.mark + return false +} + +func yaml_parser_set_scanner_tag_error(parser *yaml_parser_t, directive bool, context_mark yaml_mark_t, problem string) bool { + context := "while parsing a tag" + if directive { + context = "while parsing a %TAG directive" + } + return yaml_parser_set_scanner_error(parser, context, context_mark, problem) +} + +func trace(args ...interface{}) func() { + pargs := append([]interface{}{"+++"}, args...) + fmt.Println(pargs...) + pargs = append([]interface{}{"---"}, args...) + return func() { fmt.Println(pargs...) } +} + +// Ensure that the tokens queue contains at least one token which can be +// returned to the Parser. +func yaml_parser_fetch_more_tokens(parser *yaml_parser_t) bool { + // While we need more tokens to fetch, do it. + for { + // Check if we really need to fetch more tokens. + need_more_tokens := false + + if parser.tokens_head == len(parser.tokens) { + // Queue is empty. + need_more_tokens = true + } else { + // Check if any potential simple key may occupy the head position. + if !yaml_parser_stale_simple_keys(parser) { + return false + } + + for i := range parser.simple_keys { + simple_key := &parser.simple_keys[i] + if simple_key.possible && simple_key.token_number == parser.tokens_parsed { + need_more_tokens = true + break + } + } + } + + // We are finished. + if !need_more_tokens { + break + } + // Fetch the next token. + if !yaml_parser_fetch_next_token(parser) { + return false + } + } + + parser.token_available = true + return true +} + +// The dispatcher for token fetchers. +func yaml_parser_fetch_next_token(parser *yaml_parser_t) bool { + // Ensure that the buffer is initialized. + if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { + return false + } + + // Check if we just started scanning. Fetch STREAM-START then. + if !parser.stream_start_produced { + return yaml_parser_fetch_stream_start(parser) + } + + // Eat whitespaces and comments until we reach the next token. + if !yaml_parser_scan_to_next_token(parser) { + return false + } + + // Remove obsolete potential simple keys. + if !yaml_parser_stale_simple_keys(parser) { + return false + } + + // Check the indentation level against the current column. + if !yaml_parser_unroll_indent(parser, parser.mark.column) { + return false + } + + // Ensure that the buffer contains at least 4 characters. 4 is the length + // of the longest indicators ('--- ' and '... '). + if parser.unread < 4 && !yaml_parser_update_buffer(parser, 4) { + return false + } + + // Is it the end of the stream? + if is_z(parser.buffer, parser.buffer_pos) { + return yaml_parser_fetch_stream_end(parser) + } + + // Is it a directive? + if parser.mark.column == 0 && parser.buffer[parser.buffer_pos] == '%' { + return yaml_parser_fetch_directive(parser) + } + + buf := parser.buffer + pos := parser.buffer_pos + + // Is it the document start indicator? + if parser.mark.column == 0 && buf[pos] == '-' && buf[pos+1] == '-' && buf[pos+2] == '-' && is_blankz(buf, pos+3) { + return yaml_parser_fetch_document_indicator(parser, yaml_DOCUMENT_START_TOKEN) + } + + // Is it the document end indicator? + if parser.mark.column == 0 && buf[pos] == '.' && buf[pos+1] == '.' && buf[pos+2] == '.' && is_blankz(buf, pos+3) { + return yaml_parser_fetch_document_indicator(parser, yaml_DOCUMENT_END_TOKEN) + } + + // Is it the flow sequence start indicator? + if buf[pos] == '[' { + return yaml_parser_fetch_flow_collection_start(parser, yaml_FLOW_SEQUENCE_START_TOKEN) + } + + // Is it the flow mapping start indicator? + if parser.buffer[parser.buffer_pos] == '{' { + return yaml_parser_fetch_flow_collection_start(parser, yaml_FLOW_MAPPING_START_TOKEN) + } + + // Is it the flow sequence end indicator? + if parser.buffer[parser.buffer_pos] == ']' { + return yaml_parser_fetch_flow_collection_end(parser, + yaml_FLOW_SEQUENCE_END_TOKEN) + } + + // Is it the flow mapping end indicator? + if parser.buffer[parser.buffer_pos] == '}' { + return yaml_parser_fetch_flow_collection_end(parser, + yaml_FLOW_MAPPING_END_TOKEN) + } + + // Is it the flow entry indicator? + if parser.buffer[parser.buffer_pos] == ',' { + return yaml_parser_fetch_flow_entry(parser) + } + + // Is it the block entry indicator? + if parser.buffer[parser.buffer_pos] == '-' && is_blankz(parser.buffer, parser.buffer_pos+1) { + return yaml_parser_fetch_block_entry(parser) + } + + // Is it the key indicator? + if parser.buffer[parser.buffer_pos] == '?' && (parser.flow_level > 0 || is_blankz(parser.buffer, parser.buffer_pos+1)) { + return yaml_parser_fetch_key(parser) + } + + // Is it the value indicator? + if parser.buffer[parser.buffer_pos] == ':' && (parser.flow_level > 0 || is_blankz(parser.buffer, parser.buffer_pos+1)) { + return yaml_parser_fetch_value(parser) + } + + // Is it an alias? + if parser.buffer[parser.buffer_pos] == '*' { + return yaml_parser_fetch_anchor(parser, yaml_ALIAS_TOKEN) + } + + // Is it an anchor? + if parser.buffer[parser.buffer_pos] == '&' { + return yaml_parser_fetch_anchor(parser, yaml_ANCHOR_TOKEN) + } + + // Is it a tag? + if parser.buffer[parser.buffer_pos] == '!' { + return yaml_parser_fetch_tag(parser) + } + + // Is it a literal scalar? + if parser.buffer[parser.buffer_pos] == '|' && parser.flow_level == 0 { + return yaml_parser_fetch_block_scalar(parser, true) + } + + // Is it a folded scalar? + if parser.buffer[parser.buffer_pos] == '>' && parser.flow_level == 0 { + return yaml_parser_fetch_block_scalar(parser, false) + } + + // Is it a single-quoted scalar? + if parser.buffer[parser.buffer_pos] == '\'' { + return yaml_parser_fetch_flow_scalar(parser, true) + } + + // Is it a double-quoted scalar? + if parser.buffer[parser.buffer_pos] == '"' { + return yaml_parser_fetch_flow_scalar(parser, false) + } + + // Is it a plain scalar? + // + // A plain scalar may start with any non-blank characters except + // + // '-', '?', ':', ',', '[', ']', '{', '}', + // '#', '&', '*', '!', '|', '>', '\'', '\"', + // '%', '@', '`'. + // + // In the block context (and, for the '-' indicator, in the flow context + // too), it may also start with the characters + // + // '-', '?', ':' + // + // if it is followed by a non-space character. + // + // The last rule is more restrictive than the specification requires. + // [Go] Make this logic more reasonable. + //switch parser.buffer[parser.buffer_pos] { + //case '-', '?', ':', ',', '?', '-', ',', ':', ']', '[', '}', '{', '&', '#', '!', '*', '>', '|', '"', '\'', '@', '%', '-', '`': + //} + if !(is_blankz(parser.buffer, parser.buffer_pos) || parser.buffer[parser.buffer_pos] == '-' || + parser.buffer[parser.buffer_pos] == '?' || parser.buffer[parser.buffer_pos] == ':' || + parser.buffer[parser.buffer_pos] == ',' || parser.buffer[parser.buffer_pos] == '[' || + parser.buffer[parser.buffer_pos] == ']' || parser.buffer[parser.buffer_pos] == '{' || + parser.buffer[parser.buffer_pos] == '}' || parser.buffer[parser.buffer_pos] == '#' || + parser.buffer[parser.buffer_pos] == '&' || parser.buffer[parser.buffer_pos] == '*' || + parser.buffer[parser.buffer_pos] == '!' || parser.buffer[parser.buffer_pos] == '|' || + parser.buffer[parser.buffer_pos] == '>' || parser.buffer[parser.buffer_pos] == '\'' || + parser.buffer[parser.buffer_pos] == '"' || parser.buffer[parser.buffer_pos] == '%' || + parser.buffer[parser.buffer_pos] == '@' || parser.buffer[parser.buffer_pos] == '`') || + (parser.buffer[parser.buffer_pos] == '-' && !is_blank(parser.buffer, parser.buffer_pos+1)) || + (parser.flow_level == 0 && + (parser.buffer[parser.buffer_pos] == '?' || parser.buffer[parser.buffer_pos] == ':') && + !is_blankz(parser.buffer, parser.buffer_pos+1)) { + return yaml_parser_fetch_plain_scalar(parser) + } + + // If we don't determine the token type so far, it is an error. + return yaml_parser_set_scanner_error(parser, + "while scanning for the next token", parser.mark, + "found character that cannot start any token") +} + +// Check the list of potential simple keys and remove the positions that +// cannot contain simple keys anymore. +func yaml_parser_stale_simple_keys(parser *yaml_parser_t) bool { + // Check for a potential simple key for each flow level. + for i := range parser.simple_keys { + simple_key := &parser.simple_keys[i] + + // The specification requires that a simple key + // + // - is limited to a single line, + // - is shorter than 1024 characters. + if simple_key.possible && (simple_key.mark.line < parser.mark.line || simple_key.mark.index+1024 < parser.mark.index) { + + // Check if the potential simple key to be removed is required. + if simple_key.required { + return yaml_parser_set_scanner_error(parser, + "while scanning a simple key", simple_key.mark, + "could not find expected ':'") + } + simple_key.possible = false + } + } + return true +} + +// Check if a simple key may start at the current position and add it if +// needed. +func yaml_parser_save_simple_key(parser *yaml_parser_t) bool { + // A simple key is required at the current position if the scanner is in + // the block context and the current column coincides with the indentation + // level. + + required := parser.flow_level == 0 && parser.indent == parser.mark.column + + // A simple key is required only when it is the first token in the current + // line. Therefore it is always allowed. But we add a check anyway. + if required && !parser.simple_key_allowed { + panic("should not happen") + } + + // + // If the current position may start a simple key, save it. + // + if parser.simple_key_allowed { + simple_key := yaml_simple_key_t{ + possible: true, + required: required, + token_number: parser.tokens_parsed + (len(parser.tokens) - parser.tokens_head), + } + simple_key.mark = parser.mark + + if !yaml_parser_remove_simple_key(parser) { + return false + } + parser.simple_keys[len(parser.simple_keys)-1] = simple_key + } + return true +} + +// Remove a potential simple key at the current flow level. +func yaml_parser_remove_simple_key(parser *yaml_parser_t) bool { + i := len(parser.simple_keys) - 1 + if parser.simple_keys[i].possible { + // If the key is required, it is an error. + if parser.simple_keys[i].required { + return yaml_parser_set_scanner_error(parser, + "while scanning a simple key", parser.simple_keys[i].mark, + "could not find expected ':'") + } + } + // Remove the key from the stack. + parser.simple_keys[i].possible = false + return true +} + +// Increase the flow level and resize the simple key list if needed. +func yaml_parser_increase_flow_level(parser *yaml_parser_t) bool { + // Reset the simple key on the next level. + parser.simple_keys = append(parser.simple_keys, yaml_simple_key_t{}) + + // Increase the flow level. + parser.flow_level++ + return true +} + +// Decrease the flow level. +func yaml_parser_decrease_flow_level(parser *yaml_parser_t) bool { + if parser.flow_level > 0 { + parser.flow_level-- + parser.simple_keys = parser.simple_keys[:len(parser.simple_keys)-1] + } + return true +} + +// Push the current indentation level to the stack and set the new level +// the current column is greater than the indentation level. In this case, +// append or insert the specified token into the token queue. +func yaml_parser_roll_indent(parser *yaml_parser_t, column, number int, typ yaml_token_type_t, mark yaml_mark_t) bool { + // In the flow context, do nothing. + if parser.flow_level > 0 { + return true + } + + if parser.indent < column { + // Push the current indentation level to the stack and set the new + // indentation level. + parser.indents = append(parser.indents, parser.indent) + parser.indent = column + + // Create a token and insert it into the queue. + token := yaml_token_t{ + typ: typ, + start_mark: mark, + end_mark: mark, + } + if number > -1 { + number -= parser.tokens_parsed + } + yaml_insert_token(parser, number, &token) + } + return true +} + +// Pop indentation levels from the indents stack until the current level +// becomes less or equal to the column. For each indentation level, append +// the BLOCK-END token. +func yaml_parser_unroll_indent(parser *yaml_parser_t, column int) bool { + // In the flow context, do nothing. + if parser.flow_level > 0 { + return true + } + + // Loop through the indentation levels in the stack. + for parser.indent > column { + // Create a token and append it to the queue. + token := yaml_token_t{ + typ: yaml_BLOCK_END_TOKEN, + start_mark: parser.mark, + end_mark: parser.mark, + } + yaml_insert_token(parser, -1, &token) + + // Pop the indentation level. + parser.indent = parser.indents[len(parser.indents)-1] + parser.indents = parser.indents[:len(parser.indents)-1] + } + return true +} + +// Initialize the scanner and produce the STREAM-START token. +func yaml_parser_fetch_stream_start(parser *yaml_parser_t) bool { + + // Set the initial indentation. + parser.indent = -1 + + // Initialize the simple key stack. + parser.simple_keys = append(parser.simple_keys, yaml_simple_key_t{}) + + // A simple key is allowed at the beginning of the stream. + parser.simple_key_allowed = true |