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|
/******************************************************************
* LexMarkdown.cxx
*
* A simple Markdown lexer for scintilla.
*
* Includes highlighting for some extra features from the
* Pandoc implementation; strikeout, using '#.' as a default
* ordered list item marker, and delimited code blocks.
*
* Limitations:
*
* Standard indented code blocks are not highlighted at all,
* as it would conflict with other indentation schemes. Use
* delimited code blocks for blanket highlighting of an
* entire code block. Embedded HTML is not highlighted either.
* Blanket HTML highlighting has issues, because some Markdown
* implementations allow Markdown markup inside of the HTML. Also,
* there is a following blank line issue that can't be ignored,
* explained in the next paragraph. Embedded HTML and code
* blocks would be better supported with language specific
* highlighting.
*
* The highlighting aims to accurately reflect correct syntax,
* but a few restrictions are relaxed. Delimited code blocks are
* highlighted, even if the line following the code block is not blank.
* Requiring a blank line after a block, breaks the highlighting
* in certain cases, because of the way Scintilla ends up calling
* the lexer.
*
* Written by Jon Strait - jstrait@moonloop.net
*
* The License.txt file describes the conditions under which this
* software may be distributed.
*
*****************************************************************/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stdarg.h>
#include <assert.h>
#include "ILexer.h"
#include "Scintilla.h"
#include "SciLexer.h"
#include "WordList.h"
#include "LexAccessor.h"
#include "Accessor.h"
#include "StyleContext.h"
#include "CharacterSet.h"
#include "LexerModule.h"
#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif
static inline bool IsNewline(const int ch) {
return (ch == '\n' || ch == '\r');
}
// True if can follow ch down to the end with possibly trailing whitespace
static bool FollowToLineEnd(const int ch, const int state, const unsigned int endPos, StyleContext &sc) {
unsigned int i = 0;
while (sc.GetRelative(++i) == ch)
;
// Skip over whitespace
while (IsASpaceOrTab(sc.GetRelative(i)) && sc.currentPos + i < endPos)
++i;
if (IsNewline(sc.GetRelative(i)) || sc.currentPos + i == endPos) {
sc.Forward(i);
sc.ChangeState(state);
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
return true;
}
else return false;
}
// Set the state on text section from current to length characters,
// then set the rest until the newline to default, except for any characters matching token
static void SetStateAndZoom(const int state, const int length, const int token, StyleContext &sc) {
sc.SetState(state);
sc.Forward(length);
sc.SetState(SCE_MARKDOWN_DEFAULT);
sc.Forward();
bool started = false;
while (sc.More() && !IsNewline(sc.ch)) {
if (sc.ch == token && !started) {
sc.SetState(state);
started = true;
}
else if (sc.ch != token) {
sc.SetState(SCE_MARKDOWN_DEFAULT);
started = false;
}
sc.Forward();
}
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
}
// Does the previous line have more than spaces and tabs?
static bool HasPrevLineContent(StyleContext &sc) {
int i = 0;
// Go back to the previous newline
while ((--i + (int)sc.currentPos) >= 0 && !IsNewline(sc.GetRelative(i)))
;
while ((--i + (int)sc.currentPos) >= 0) {
if (IsNewline(sc.GetRelative(i)))
break;
if (!IsASpaceOrTab(sc.GetRelative(i)))
return true;
}
return false;
}
static bool IsValidHrule(const unsigned int endPos, StyleContext &sc) {
int c, count = 1;
unsigned int i = 0;
while (++i) {
c = sc.GetRelative(i);
if (c == sc.ch)
++count;
// hit a terminating character
else if (!IsASpaceOrTab(c) || sc.currentPos + i == endPos) {
// Are we a valid HRULE
if ((IsNewline(c) || sc.currentPos + i == endPos) &&
count >= 3 && !HasPrevLineContent(sc)) {
sc.SetState(SCE_MARKDOWN_HRULE);
sc.Forward(i);
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
return true;
}
else {
sc.SetState(SCE_MARKDOWN_DEFAULT);
return false;
}
}
}
return false;
}
static void ColorizeMarkdownDoc(unsigned int startPos, int length, int initStyle,
WordList **, Accessor &styler) {
unsigned int endPos = startPos + length;
int precharCount = 0;
// Don't advance on a new loop iteration and retry at the same position.
// Useful in the corner case of having to start at the beginning file position
// in the default state.
bool freezeCursor = false;
StyleContext sc(startPos, length, initStyle, styler);
while (sc.More()) {
// Skip past escaped characters
if (sc.ch == '\\') {
sc.Forward();
continue;
}
// A blockquotes resets the line semantics
if (sc.state == SCE_MARKDOWN_BLOCKQUOTE)
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
// Conditional state-based actions
if (sc.state == SCE_MARKDOWN_CODE2) {
if (sc.Match("``") && sc.GetRelative(-2) != ' ') {
sc.Forward(2);
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
}
else if (sc.state == SCE_MARKDOWN_CODE) {
if (sc.ch == '`' && sc.chPrev != ' ')
sc.ForwardSetState(SCE_MARKDOWN_DEFAULT);
}
/* De-activated because it gets in the way of other valid indentation
* schemes, for example multiple paragraphs inside a list item.
// Code block
else if (sc.state == SCE_MARKDOWN_CODEBK) {
bool d = true;
if (IsNewline(sc.ch)) {
if (sc.chNext != '\t') {
for (int c = 1; c < 5; ++c) {
if (sc.GetRelative(c) != ' ')
d = false;
}
}
}
else if (sc.atLineStart) {
if (sc.ch != '\t' ) {
for (int i = 0; i < 4; ++i) {
if (sc.GetRelative(i) != ' ')
d = false;
}
}
}
if (!d)
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
}
*/
// Strong
else if (sc.state == SCE_MARKDOWN_STRONG1) {
if (sc.Match("**") && sc.chPrev != ' ') {
sc.Forward(2);
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
}
else if (sc.state == SCE_MARKDOWN_STRONG2) {
if (sc.Match("__") && sc.chPrev != ' ') {
sc.Forward(2);
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
}
// Emphasis
else if (sc.state == SCE_MARKDOWN_EM1) {
if (sc.ch == '*' && sc.chPrev != ' ')
sc.ForwardSetState(SCE_MARKDOWN_DEFAULT);
}
else if (sc.state == SCE_MARKDOWN_EM2) {
if (sc.ch == '_' && sc.chPrev != ' ')
sc.ForwardSetState(SCE_MARKDOWN_DEFAULT);
}
else if (sc.state == SCE_MARKDOWN_CODEBK) {
if (sc.atLineStart && sc.Match("~~~")) {
int i = 1;
while (!IsNewline(sc.GetRelative(i)) && sc.currentPos + i < endPos)
i++;
sc.Forward(i);
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
}
else if (sc.state == SCE_MARKDOWN_STRIKEOUT) {
if (sc.Match("~~") && sc.chPrev != ' ') {
sc.Forward(2);
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
}
else if (sc.state == SCE_MARKDOWN_LINE_BEGIN) {
// Header
if (sc.Match("######"))
SetStateAndZoom(SCE_MARKDOWN_HEADER6, 6, '#', sc);
else if (sc.Match("#####"))
SetStateAndZoom(SCE_MARKDOWN_HEADER5, 5, '#', sc);
else if (sc.Match("####"))
SetStateAndZoom(SCE_MARKDOWN_HEADER4, 4, '#', sc);
else if (sc.Match("###"))
SetStateAndZoom(SCE_MARKDOWN_HEADER3, 3, '#', sc);
else if (sc.Match("##"))
SetStateAndZoom(SCE_MARKDOWN_HEADER2, 2, '#', sc);
else if (sc.Match("#")) {
// Catch the special case of an unordered list
if (sc.chNext == '.' && IsASpaceOrTab(sc.GetRelative(2))) {
precharCount = 0;
sc.SetState(SCE_MARKDOWN_PRECHAR);
}
else
SetStateAndZoom(SCE_MARKDOWN_HEADER1, 1, '#', sc);
}
// Code block
else if (sc.Match("~~~")) {
if (!HasPrevLineContent(sc))
sc.SetState(SCE_MARKDOWN_CODEBK);
else
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
else if (sc.ch == '=') {
if (HasPrevLineContent(sc) && FollowToLineEnd('=', SCE_MARKDOWN_HEADER1, endPos, sc))
;
else
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
else if (sc.ch == '-') {
if (HasPrevLineContent(sc) && FollowToLineEnd('-', SCE_MARKDOWN_HEADER2, endPos, sc))
;
else {
precharCount = 0;
sc.SetState(SCE_MARKDOWN_PRECHAR);
}
}
else if (IsNewline(sc.ch))
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
else {
precharCount = 0;
sc.SetState(SCE_MARKDOWN_PRECHAR);
}
}
// The header lasts until the newline
else if (sc.state == SCE_MARKDOWN_HEADER1 || sc.state == SCE_MARKDOWN_HEADER2 ||
sc.state == SCE_MARKDOWN_HEADER3 || sc.state == SCE_MARKDOWN_HEADER4 ||
sc.state == SCE_MARKDOWN_HEADER5 || sc.state == SCE_MARKDOWN_HEADER6) {
if (IsNewline(sc.ch))
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
}
// New state only within the initial whitespace
if (sc.state == SCE_MARKDOWN_PRECHAR) {
// Blockquote
if (sc.ch == '>' && precharCount < 5)
sc.SetState(SCE_MARKDOWN_BLOCKQUOTE);
/*
// Begin of code block
else if (!HasPrevLineContent(sc) && (sc.chPrev == '\t' || precharCount >= 4))
sc.SetState(SCE_MARKDOWN_CODEBK);
*/
// HRule - Total of three or more hyphens, asterisks, or underscores
// on a line by themselves
else if ((sc.ch == '-' || sc.ch == '*' || sc.ch == '_') && IsValidHrule(endPos, sc))
;
// Unordered list
else if ((sc.ch == '-' || sc.ch == '*' || sc.ch == '+') && IsASpaceOrTab(sc.chNext)) {
sc.SetState(SCE_MARKDOWN_ULIST_ITEM);
sc.ForwardSetState(SCE_MARKDOWN_DEFAULT);
}
// Ordered list
else if (IsADigit(sc.ch)) {
int digitCount = 0;
while (IsADigit(sc.GetRelative(++digitCount)))
;
if (sc.GetRelative(digitCount) == '.' &&
IsASpaceOrTab(sc.GetRelative(digitCount + 1))) {
sc.SetState(SCE_MARKDOWN_OLIST_ITEM);
sc.Forward(digitCount + 1);
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
}
// Alternate Ordered list
else if (sc.ch == '#' && sc.chNext == '.' && IsASpaceOrTab(sc.GetRelative(2))) {
sc.SetState(SCE_MARKDOWN_OLIST_ITEM);
sc.Forward(2);
sc.SetState(SCE_MARKDOWN_DEFAULT);
}
else if (sc.ch != ' ' || precharCount > 2)
sc.SetState(SCE_MARKDOWN_DEFAULT);
else
++precharCount;
}
// New state anywhere in doc
if (sc.state == SCE_MARKDOWN_DEFAULT) {
if (sc.atLineStart && sc.ch == '#') {
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
freezeCursor = true;
}
// Links and Images
if (sc.Match("![") || sc.ch == '[') {
int i = 0, j = 0, k = 0;
int len = endPos - sc.currentPos;
while (i < len && (sc.GetRelative(++i) != ']' || sc.GetRelative(i - 1) == '\\'))
;
if (sc.GetRelative(i) == ']') {
j = i;
if (sc.GetRelative(++i) == '(') {
while (i < len && (sc.GetRelative(++i) != ')' || sc.GetRelative(i - 1) == '\\'))
;
if (sc.GetRelative(i) == ')')
k = i;
}
else if (sc.GetRelative(i) == '[' || sc.GetRelative(++i) == '[') {
while (i < len && (sc.GetRelative(++i) != ']' || sc.GetRelative(i - 1) == '\\'))
;
if (sc.GetRelative(i) == ']')
k = i;
}
}
// At least a link text
if (j) {
sc.SetState(SCE_MARKDOWN_LINK);
sc.Forward(j);
// Also has a URL or reference portion
if (k)
sc.Forward(k - j);
sc.ForwardSetState(SCE_MARKDOWN_DEFAULT);
}
}
// Code - also a special case for alternate inside spacing
if (sc.Match("``") && sc.GetRelative(3) != ' ') {
sc.SetState(SCE_MARKDOWN_CODE2);
sc.Forward();
}
else if (sc.ch == '`' && sc.chNext != ' ') {
sc.SetState(SCE_MARKDOWN_CODE);
}
// Strong
else if (sc.Match("**") && sc.GetRelative(2) != ' ') {
sc.SetState(SCE_MARKDOWN_STRONG1);
sc.Forward();
}
else if (sc.Match("__") && sc.GetRelative(2) != ' ') {
sc.SetState(SCE_MARKDOWN_STRONG2);
sc.Forward();
}
// Emphasis
else if (sc.ch == '*' && sc.chNext != ' ')
sc.SetState(SCE_MARKDOWN_EM1);
else if (sc.ch == '_' && sc.chNext != ' ')
sc.SetState(SCE_MARKDOWN_EM2);
// Strikeout
else if (sc.Match("~~") && sc.GetRelative(2) != ' ') {
sc.SetState(SCE_MARKDOWN_STRIKEOUT);
sc.Forward();
}
// Beginning of line
else if (IsNewline(sc.ch))
sc.SetState(SCE_MARKDOWN_LINE_BEGIN);
}
// Advance if not holding back the cursor for this iteration.
if (!freezeCursor)
sc.Forward();
freezeCursor = false;
}
sc.Complete();
}
LexerModule lmMarkdown(SCLEX_MARKDOWN, ColorizeMarkdownDoc, "markdown");
|