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Diffstat (limited to 'src/LexMarkdown.cxx')
| -rw-r--r-- | src/LexMarkdown.cxx | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/src/LexMarkdown.cxx b/src/LexMarkdown.cxx new file mode 100644 index 000000000..f7fc48f40 --- /dev/null +++ b/src/LexMarkdown.cxx @@ -0,0 +1,412 @@ +/****************************************************************** + * 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 <ctype.h> +#include <stdio.h> +#include <stdarg.h> + +#include "Platform.h" + +#include "PropSet.h" +#include "Accessor.h" +#include "StyleContext.h" +#include "KeyWords.h" +#include "Scintilla.h" +#include "SciLexer.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 + sc.currentPos) && !IsNewline(sc.GetRelative(i))) + ; + while (--i + sc.currentPos) { + 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"); |