README
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indents
Package indents provides functions for parsing text with indentation.
Documentation
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Overview ¶
Package indents provides functions for parsing text with indentation.
Index ¶
Examples ¶
Constants ¶
const ( Space = ' ' Tab = '\t' )
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type ExtraIndentationError ¶
type ExtraIndentationError struct {
Line int // Line number where the error is found.
}
func (*ExtraIndentationError) Error ¶
func (e *ExtraIndentationError) Error() string
type IndentScanner ¶
type IndentScanner struct {
// contains filtered or unexported fields
}
Provides a bufio.Scanner-like interface for reading indented-text. Successive calls to the Scan method will step through the lines of a file. Call the Line method to get the current *Line struct, with the indentation level calculated and set.
The IndentScanner is indentation-"dumb", it merely detects the indentation size of each line and sets it on the *Line struct. It's up to the caller to assert any indentation-aware logic.
See the ParseNodeTree function, where Lines produced by this scanner are parsed in an indentation-aware manner and converted into a tree structure.
Example ¶
text := "line one\n"
text += " line 2\n"
text += " line\n"
text += "four"
reader := strings.NewReader(text)
scanner := NewIndentScanner(reader, nil)
for scanner.Scan() {
line := scanner.Line()
fmt.Printf(
"Line %d, level %d: '%s'\n",
line.Number,
line.Level,
line.Text,
)
}
Output: Line 1, level 0: 'line one' Line 2, level 1: 'line 2' Line 3, level 2: 'line' Line 4, level 0: 'four'
func NewIndentScanner ¶
func NewIndentScanner(r io.Reader, style *Style) *IndentScanner
Creates a new IndentScanner that reads data from Reader r. The style argument sets the assumed indentation style of the data. If it's nil, the scanner will try to auto-detect the style using the AutoDetect function.
func (*IndentScanner) Err ¶
func (s *IndentScanner) Err() error
Returns the first non-EOF error that was encountered by the Scanner.
func (*IndentScanner) Line ¶
func (s *IndentScanner) Line() *Line
Returns the most recent line generated by a call to Scan as a newly allocated Line struct.
func (*IndentScanner) Lines ¶
func (s *IndentScanner) Lines() int
Returns the number of lines read. Will return 0 if the Scan method was never called before.
func (*IndentScanner) Scan ¶
func (s *IndentScanner) Scan() bool
Advance the scanner to the next line, which will then be available through the Line method. It returns false when the scan stops, either by reaching the end of the input or an error. After Scan returns false, the Err method will return any error that occurred during scanning, except that if it was io.EOF, Err will return nil.
func (*IndentScanner) Style ¶
func (s *IndentScanner) Style() *Style
Returns the autodetected indent style. Will return nil if no indetation detected, or the Line method was never called before.
type Line ¶
type Line struct {
Text string // The line text without indentation.
Number int // The line number.
Level int // The indentation level.
}
Encapsulates an indented line.
type Node ¶
type Node struct {
Line *Line // The corresponding Line
Parent *Node // This node's parent node
Children []*Node // This node's child nodes
}
Encapsulates a node in a tree.
func ParseNodeTree ¶
func ParseNodeTree( scanner *IndentScanner, root *Node, options *ParseNodeTreeOptions, ) (*Node, error)
Read lines from an IndentScanner and produce a node tree sructure.
Behaviour of the parser can be customized with the options argument. See ParseNodeTreeOptions.
func (*Node) IsAboveLevel ¶
Tests if this node's indentation level is above o's.
func (*Node) IsBelowLevel ¶
Tests if this node's indentation level is below o's.
func (*Node) IsSameLevel ¶
Tests if this node's indentation level is the same as o's.
type NodeProcessor ¶
type NodeProcessor func(node *Node, options *ParseNodeTreeOptions) error
Function to process nodes generated from ParseNodeTree
type ParseNodeTreeOptions ¶
type ParseNodeTreeOptions struct {
// If true, extra indentations will be ignored.
IgnoreExtraIndentation bool
// If set, this function will be called on each Node generated.
Processor NodeProcessor
}
Options to pass to ParseNodeTree function to customize its behaviour.
type Style ¶
type Style struct {
Char rune // The indent character.
Size int // Number of subsequent Char's considered as 1 indent.
}
Encapsulates an indentation style.
func AutoDetect ¶
Create a new Style by auto-detecting indentation of given line. It is assumed that the given line has (potentially) a first-level indentation. If there are no indentation in the line, this function will return nil.
Example ¶
style := AutoDetect(" two spaces")
fmt.Printf("Style.Char: [%c]\n", style.Char)
fmt.Printf("Style.Size: %d\n", style.Size)
Output: Style.Char: [ ] Style.Size: 2
func (*Style) Level ¶
Calculate the given line's indentation level based on this indent style.
Example ¶
// Even numbered indents:
style := &Style{Char: '.', Size: 2}
fmt.Println(style.Level("..two spaces in")) // Level=1
fmt.Println(style.Level("....four spaces")) // Levels=2
fmt.Println(style.Level(".....five space")) // Levels=2 (rounds to Size)
// Odd numbered indents are also ok:
oddStyle := &Style{Char: '-', Size: 3}
fmt.Println(oddStyle.Level("---three spaces")) // Level=1
fmt.Println(oddStyle.Level("------six space")) // Levels=2
fmt.Println(oddStyle.Level("-------seven sp")) // Levels=2
Output: 1 2 2 1 2 2
Source Files