477 lines
14 KiB
Go
477 lines
14 KiB
Go
// Copyright 2006-2010 Kirill Simonov
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// Copyright 2011-2019 Canonical Ltd
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// Copyright 2025 The go-yaml Project Contributors
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// SPDX-License-Identifier: Apache-2.0 AND MIT
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// Core libyaml types and structures.
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// Defines Parser, Emitter, Event, Token, and related constants for YAML
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// processing.
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package libyaml
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import (
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"fmt"
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"strings"
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)
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// VersionDirective holds the YAML version directive data.
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type VersionDirective struct {
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major int8 // The major version number.
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minor int8 // The minor version number.
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}
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// Major returns the major version number.
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func (v *VersionDirective) Major() int { return int(v.major) }
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// Minor returns the minor version number.
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func (v *VersionDirective) Minor() int { return int(v.minor) }
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// TagDirective holds the YAML tag directive data.
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type TagDirective struct {
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handle []byte // The tag handle.
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prefix []byte // The tag prefix.
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}
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// GetHandle returns the tag handle.
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func (t *TagDirective) GetHandle() string { return string(t.handle) }
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// GetPrefix returns the tag prefix.
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func (t *TagDirective) GetPrefix() string { return string(t.prefix) }
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// Encoding represents the character encoding of a YAML stream.
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type Encoding int
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// The stream encoding.
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const (
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// Let the parser choose the encoding.
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ANY_ENCODING Encoding = iota
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UTF8_ENCODING // The default UTF-8 encoding.
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UTF16LE_ENCODING // The UTF-16-LE encoding with BOM.
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UTF16BE_ENCODING // The UTF-16-BE encoding with BOM.
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)
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// LineBreak represents the line break style used in YAML output.
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type LineBreak int
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// Line break types.
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const (
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// Let the parser choose the break type.
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ANY_BREAK LineBreak = iota
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CR_BREAK // Use CR for line breaks (Mac style).
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LN_BREAK // Use LN for line breaks (Unix style).
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CRLN_BREAK // Use CR LN for line breaks (DOS style).
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)
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// QuoteStyle represents the preferred quote style for scalar values.
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type QuoteStyle int
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// Quote style types for required quoting.
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const (
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QuoteSingle QuoteStyle = iota // Prefer single quotes when quoting is required.
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QuoteDouble // Prefer double quotes when quoting is required.
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QuoteLegacy // Legacy behavior: double in representer, single in emitter.
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)
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// ScalarStyle returns the scalar style for this quote preference in the
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// representer/serializer context.
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// In this context, both QuoteDouble and QuoteLegacy use double quotes.
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func (q QuoteStyle) ScalarStyle() ScalarStyle {
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if q == QuoteDouble || q == QuoteLegacy {
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return DOUBLE_QUOTED_SCALAR_STYLE
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}
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return SINGLE_QUOTED_SCALAR_STYLE
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}
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// ErrorType represents the category of error that occurred during processing.
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type ErrorType int
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// Many bad things could happen with the parser and emitter.
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const (
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// No error is produced.
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NO_ERROR ErrorType = iota
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MEMORY_ERROR // Cannot allocate or reallocate a block of memory.
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READER_ERROR // Cannot read or decode the input stream.
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SCANNER_ERROR // Cannot scan the input stream.
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PARSER_ERROR // Cannot parse the input stream.
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COMPOSER_ERROR // Cannot compose a YAML document.
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WRITER_ERROR // Cannot write to the output stream.
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EMITTER_ERROR // Cannot emit a YAML stream.
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)
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// Mark holds the pointer position.
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type Mark struct {
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Index int // The position index.
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Line int // The position line (1-indexed; 0 means unknown).
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Column int // The position column (1-indexed; 0 means unknown).
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}
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// String returns a human-readable string representation of the position mark.
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func (m Mark) String() string {
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var builder strings.Builder
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if m.Line == 0 {
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return "<unknown position>"
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}
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fmt.Fprintf(&builder, "line %d", m.Line)
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if m.Column > 0 {
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fmt.Fprintf(&builder, ", column %d", m.Column)
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}
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return builder.String()
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}
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// shortString returns a compact position string.
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// Returns "<unknown position>" when Line is 0 (position not known).
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// When Column is 0 (unknown), it is omitted from output ("L{line}");
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// otherwise it is displayed as "L{line}.C{col}".
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func (m Mark) shortString() string {
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if m.Line == 0 {
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return "<unknown position>"
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}
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if m.Column > 0 {
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return fmt.Sprintf("L%d.C%d", m.Line, m.Column)
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}
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return fmt.Sprintf("L%d", m.Line)
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}
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// rangeString formats a position range from start mark m to end mark.
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// Both marks use shortString for their individual display.
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// When marks are on the same line:
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// - Both Column==0: just "L2" (unknown columns, no range shown)
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// - Both Column>0: "L2.C6-C7" (compact column range)
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// - Mixed columns: "L1.C4-L1" (full start with line-only end)
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//
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// When marks are on different lines: "L1.C8-L2.C3"
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func (m Mark) rangeString(end Mark) string {
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start := m.shortString()
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if m.Line == end.Line {
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if m.Column == 0 && end.Column == 0 {
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// Same line, unknown columns: just "L2"
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return start
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}
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if m.Column > 0 && end.Column > 0 {
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if m.Column == end.Column {
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// Same position: just "L2.C6"
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return start
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}
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// Same line with columns: "L2.C6-C7"
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return fmt.Sprintf("%s-C%d", start, end.Column)
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}
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}
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return fmt.Sprintf("%s-%s", start, end.shortString())
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}
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// Node Styles
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// styleInt is the underlying type for style constants.
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type styleInt int8
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// ScalarStyle represents the formatting style of a scalar value.
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type ScalarStyle styleInt
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// Scalar styles.
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const (
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// Let the emitter choose the style.
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ANY_SCALAR_STYLE ScalarStyle = 0
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PLAIN_SCALAR_STYLE ScalarStyle = 1 << iota // The plain scalar style.
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SINGLE_QUOTED_SCALAR_STYLE // The single-quoted scalar style.
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DOUBLE_QUOTED_SCALAR_STYLE // The double-quoted scalar style.
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LITERAL_SCALAR_STYLE // The literal scalar style.
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FOLDED_SCALAR_STYLE // The folded scalar style.
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)
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// String returns a string representation of a [ScalarStyle].
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func (style ScalarStyle) String() string {
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switch style {
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case PLAIN_SCALAR_STYLE:
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return "Plain"
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case SINGLE_QUOTED_SCALAR_STYLE:
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return "Single"
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case DOUBLE_QUOTED_SCALAR_STYLE:
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return "Double"
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case LITERAL_SCALAR_STYLE:
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return "Literal"
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case FOLDED_SCALAR_STYLE:
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return "Folded"
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default:
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return ""
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}
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}
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// SequenceStyle represents the formatting style of a sequence node.
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type SequenceStyle styleInt
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// Sequence styles.
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const (
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// Let the emitter choose the style.
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ANY_SEQUENCE_STYLE SequenceStyle = iota
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BLOCK_SEQUENCE_STYLE // The block sequence style.
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FLOW_SEQUENCE_STYLE // The flow sequence style.
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)
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// MappingStyle represents the formatting style of a mapping node.
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type MappingStyle styleInt
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// Mapping styles.
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const (
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// Let the emitter choose the style.
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ANY_MAPPING_STYLE MappingStyle = iota
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BLOCK_MAPPING_STYLE // The block mapping style.
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FLOW_MAPPING_STYLE // The flow mapping style.
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)
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// Tokens
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// TokenType represents the type of a scanned token.
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type TokenType int
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// Token types.
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const (
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// An empty token.
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NO_TOKEN TokenType = iota
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STREAM_START_TOKEN // A STREAM-START token.
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STREAM_END_TOKEN // A STREAM-END token.
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VERSION_DIRECTIVE_TOKEN // A VERSION-DIRECTIVE token.
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TAG_DIRECTIVE_TOKEN // A TAG-DIRECTIVE token.
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DOCUMENT_START_TOKEN // A DOCUMENT-START token.
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DOCUMENT_END_TOKEN // A DOCUMENT-END token.
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BLOCK_SEQUENCE_START_TOKEN // A BLOCK-SEQUENCE-START token.
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BLOCK_MAPPING_START_TOKEN // A BLOCK-SEQUENCE-END token.
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BLOCK_END_TOKEN // A BLOCK-END token.
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FLOW_SEQUENCE_START_TOKEN // A FLOW-SEQUENCE-START token.
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FLOW_SEQUENCE_END_TOKEN // A FLOW-SEQUENCE-END token.
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FLOW_MAPPING_START_TOKEN // A FLOW-MAPPING-START token.
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FLOW_MAPPING_END_TOKEN // A FLOW-MAPPING-END token.
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BLOCK_ENTRY_TOKEN // A BLOCK-ENTRY token.
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FLOW_ENTRY_TOKEN // A FLOW-ENTRY token.
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KEY_TOKEN // A KEY token.
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VALUE_TOKEN // A VALUE token.
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ALIAS_TOKEN // An ALIAS token.
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ANCHOR_TOKEN // An ANCHOR token.
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TAG_TOKEN // A TAG token.
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SCALAR_TOKEN // A SCALAR token.
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COMMENT_TOKEN // A COMMENT token.
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)
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// String returns a string representation of the token type.
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func (tt TokenType) String() string {
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switch tt {
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case NO_TOKEN:
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return "NO_TOKEN"
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case STREAM_START_TOKEN:
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return "STREAM_START_TOKEN"
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case STREAM_END_TOKEN:
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return "STREAM_END_TOKEN"
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case VERSION_DIRECTIVE_TOKEN:
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return "VERSION_DIRECTIVE_TOKEN"
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case TAG_DIRECTIVE_TOKEN:
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return "TAG_DIRECTIVE_TOKEN"
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case DOCUMENT_START_TOKEN:
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return "DOCUMENT_START_TOKEN"
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case DOCUMENT_END_TOKEN:
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return "DOCUMENT_END_TOKEN"
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case BLOCK_SEQUENCE_START_TOKEN:
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return "BLOCK_SEQUENCE_START_TOKEN"
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case BLOCK_MAPPING_START_TOKEN:
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return "BLOCK_MAPPING_START_TOKEN"
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case BLOCK_END_TOKEN:
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return "BLOCK_END_TOKEN"
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case FLOW_SEQUENCE_START_TOKEN:
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return "FLOW_SEQUENCE_START_TOKEN"
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case FLOW_SEQUENCE_END_TOKEN:
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return "FLOW_SEQUENCE_END_TOKEN"
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case FLOW_MAPPING_START_TOKEN:
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return "FLOW_MAPPING_START_TOKEN"
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case FLOW_MAPPING_END_TOKEN:
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return "FLOW_MAPPING_END_TOKEN"
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case BLOCK_ENTRY_TOKEN:
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return "BLOCK_ENTRY_TOKEN"
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case FLOW_ENTRY_TOKEN:
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return "FLOW_ENTRY_TOKEN"
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case KEY_TOKEN:
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return "KEY_TOKEN"
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case VALUE_TOKEN:
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return "VALUE_TOKEN"
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case ALIAS_TOKEN:
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return "ALIAS_TOKEN"
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case ANCHOR_TOKEN:
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return "ANCHOR_TOKEN"
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case TAG_TOKEN:
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return "TAG_TOKEN"
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case SCALAR_TOKEN:
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return "SCALAR_TOKEN"
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case COMMENT_TOKEN:
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return "COMMENT_TOKEN"
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}
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return "<unknown token>"
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}
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// Token holds information about a scanning token.
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type Token struct {
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// The token type.
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Type TokenType
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// The start/end of the token.
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StartMark, EndMark Mark
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// The stream encoding (for STREAM_START_TOKEN).
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encoding Encoding
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// The alias/anchor/scalar Value or tag/tag directive handle
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// (for ALIAS_TOKEN, ANCHOR_TOKEN, SCALAR_TOKEN, TAG_TOKEN, TAG_DIRECTIVE_TOKEN).
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Value []byte
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// The tag suffix (for TAG_TOKEN).
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suffix []byte
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// The tag directive prefix (for TAG_DIRECTIVE_TOKEN).
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prefix []byte
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// The scalar Style (for SCALAR_TOKEN).
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Style ScalarStyle
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// The version directive major/minor (for VERSION_DIRECTIVE_TOKEN).
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major, minor int8
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}
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// Events
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// EventType represents the type of a parsing or emitting event.
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type EventType int8
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// Event types.
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const (
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// An empty event.
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NO_EVENT EventType = iota
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STREAM_START_EVENT // A STREAM-START event.
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STREAM_END_EVENT // A STREAM-END event.
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DOCUMENT_START_EVENT // A DOCUMENT-START event.
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DOCUMENT_END_EVENT // A DOCUMENT-END event.
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ALIAS_EVENT // An ALIAS event.
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SCALAR_EVENT // A SCALAR event.
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SEQUENCE_START_EVENT // A SEQUENCE-START event.
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SEQUENCE_END_EVENT // A SEQUENCE-END event.
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MAPPING_START_EVENT // A MAPPING-START event.
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MAPPING_END_EVENT // A MAPPING-END event.
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TAIL_COMMENT_EVENT
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)
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// eventStrings maps EventType constants to their string representations.
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var eventStrings = []string{
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NO_EVENT: "none",
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STREAM_START_EVENT: "stream start",
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STREAM_END_EVENT: "stream end",
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DOCUMENT_START_EVENT: "document start",
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DOCUMENT_END_EVENT: "document end",
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ALIAS_EVENT: "alias",
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SCALAR_EVENT: "scalar",
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SEQUENCE_START_EVENT: "sequence start",
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SEQUENCE_END_EVENT: "sequence end",
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MAPPING_START_EVENT: "mapping start",
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MAPPING_END_EVENT: "mapping end",
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TAIL_COMMENT_EVENT: "tail comment",
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}
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// String returns a string representation of the event type.
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func (e EventType) String() string {
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if e < 0 || int(e) >= len(eventStrings) {
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return fmt.Sprintf("unknown event %d", e)
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}
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return eventStrings[e]
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}
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// Event holds information about a parsing or emitting event.
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type Event struct {
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// The event type.
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Type EventType
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// The start and end of the event.
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StartMark, EndMark Mark
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// The document encoding (for STREAM_START_EVENT).
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encoding Encoding
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// The version directive (for DOCUMENT_START_EVENT).
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versionDirective *VersionDirective
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// The list of tag directives (for DOCUMENT_START_EVENT).
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tagDirectives []TagDirective
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// The comments
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HeadComment []byte
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LineComment []byte
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FootComment []byte
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TailComment []byte
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// The Anchor (for SCALAR_EVENT, SEQUENCE_START_EVENT, MAPPING_START_EVENT, ALIAS_EVENT).
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Anchor []byte
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// The Tag (for SCALAR_EVENT, SEQUENCE_START_EVENT, MAPPING_START_EVENT).
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Tag []byte
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// The scalar Value (for SCALAR_EVENT).
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Value []byte
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// Is the document start/end indicator Implicit, or the tag optional?
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// (for DOCUMENT_START_EVENT, DOCUMENT_END_EVENT, SEQUENCE_START_EVENT, MAPPING_START_EVENT, SCALAR_EVENT).
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Implicit bool
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// Is the tag optional for any non-plain style? (for SCALAR_EVENT).
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quoted_implicit bool
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// The Style (for SCALAR_EVENT, SEQUENCE_START_EVENT, MAPPING_START_EVENT).
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Style Style
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}
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// ScalarStyle returns the style of a scalar event.
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func (e *Event) ScalarStyle() ScalarStyle { return ScalarStyle(e.Style) }
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// SequenceStyle returns the style of a sequence event.
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func (e *Event) SequenceStyle() SequenceStyle { return SequenceStyle(e.Style) }
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// MappingStyle returns the style of a mapping event.
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func (e *Event) MappingStyle() MappingStyle { return MappingStyle(e.Style) }
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// GetEncoding returns the stream encoding (for STREAM_START_EVENT).
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func (e *Event) GetEncoding() Encoding { return e.encoding }
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// GetVersionDirective returns the version directive (for DOCUMENT_START_EVENT).
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func (e *Event) GetVersionDirective() *VersionDirective { return e.versionDirective }
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// GetTagDirectives returns the tag directives (for DOCUMENT_START_EVENT).
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func (e *Event) GetTagDirectives() []TagDirective { return e.tagDirectives }
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// Nodes
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const (
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NULL_TAG = "tag:yaml.org,2002:null" // The tag !!null with the only possible value: null.
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BOOL_TAG = "tag:yaml.org,2002:bool" // The tag !!bool with the values: true and false.
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STR_TAG = "tag:yaml.org,2002:str" // The tag !!str for string values.
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INT_TAG = "tag:yaml.org,2002:int" // The tag !!int for integer values.
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FLOAT_TAG = "tag:yaml.org,2002:float" // The tag !!float for float values.
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TIMESTAMP_TAG = "tag:yaml.org,2002:timestamp" // The tag !!timestamp for date and time values.
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SEQ_TAG = "tag:yaml.org,2002:seq" // The tag !!seq is used to denote sequences.
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MAP_TAG = "tag:yaml.org,2002:map" // The tag !!map is used to denote mapping.
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// Not in original libyaml.
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BINARY_TAG = "tag:yaml.org,2002:binary"
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MERGE_TAG = "tag:yaml.org,2002:merge"
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DEFAULT_SCALAR_TAG = STR_TAG // The default scalar tag is !!str.
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DEFAULT_SEQUENCE_TAG = SEQ_TAG // The default sequence tag is !!seq.
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DEFAULT_MAPPING_TAG = MAP_TAG // The default mapping tag is !!map.
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)
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