break.go

     1  // Copyright 2021 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package markdown
     6  
     7  import (
     8  	"bytes"
     9  )
    10  
    11  type ThematicBreak struct {
    12  	Position
    13  	raw string
    14  }
    15  
    16  func (b *ThematicBreak) PrintHTML(buf *bytes.Buffer) {
    17  	buf.WriteString("<hr />\n")
    18  }
    19  
    20  func (b *ThematicBreak) printMarkdown(buf *bytes.Buffer, s mdState) {
    21  	buf.WriteString(s.prefix)
    22  	buf.WriteString(b.raw)
    23  	buf.WriteByte('\n')
    24  }
    25  
    26  func newHR(p *parseState, s line) (line, bool) {
    27  	if isHR(s) {
    28  		p.doneBlock(&ThematicBreak{Position{p.lineno, p.lineno}, s.string()})
    29  		return line{}, true
    30  	}
    31  	return s, false
    32  }
    33  
    34  func isHR(s line) bool {
    35  	t := s
    36  	t.trimSpace(0, 3, false)
    37  	switch c := t.peek(); c {
    38  	case '-', '_', '*':
    39  		for i := 0; ; i++ {
    40  			if !t.trim(c) {
    41  				if i >= 3 {
    42  					break
    43  				}
    44  				return false
    45  			}
    46  			t.skipSpace()
    47  		}
    48  		return t.eof()
    49  	}
    50  	return false
    51  }
    52  
    53  type HardBreak struct{}
    54  
    55  func (*HardBreak) Inline() {}
    56  
    57  func (x *HardBreak) PrintHTML(buf *bytes.Buffer) {
    58  	buf.WriteString("<br />\n")
    59  }
    60  
    61  func (x *HardBreak) printMarkdown(buf *bytes.Buffer) {
    62  	buf.WriteString("\\\n")
    63  }
    64  
    65  func (x *HardBreak) PrintText(buf *bytes.Buffer) {
    66  	buf.WriteString("\n")
    67  }
    68  
    69  type SoftBreak struct{}
    70  
    71  func (*SoftBreak) Inline() {}
    72  
    73  func (x *SoftBreak) PrintHTML(buf *bytes.Buffer) {
    74  	buf.WriteString("\n")
    75  }
    76  
    77  func (x *SoftBreak) printMarkdown(buf *bytes.Buffer) {
    78  	buf.WriteString("\n")
    79  }
    80  
    81  func (x *SoftBreak) PrintText(buf *bytes.Buffer) {
    82  	buf.WriteString("\n")
    83  }
    84  
    85  func parseBreak(_ *parseState, s string, i int) (Inline, int, int, bool) {
    86  	start := i
    87  	for start > 0 && (s[start-1] == ' ' || s[start-1] == '\t') {
    88  		start--
    89  	}
    90  	end := i + 1
    91  	for end < len(s) && (s[end] == ' ' || s[end] == '\t') {
    92  		end++
    93  	}
    94  	// TODO: Do tabs count? That would be a mess.
    95  	if i >= 2 && s[i-1] == ' ' && s[i-2] == ' ' {
    96  		return &HardBreak{}, start, end, true
    97  	}
    98  	return &SoftBreak{}, start, end, true
    99  }
   100
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