lexruby.cxx

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// Scintilla source code edit control
/** @file LexRuby.cxx
 ** Lexer for Ruby.
 **/
// Copyright 2001- by Clemens Wyss <[e-mail]>
// 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 "KeyWords.h"
#include "Scintilla.h"
#include "SciLexer.h"

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

//XXX Identical to Perl, put in common area
static inline bool isEOLChar(char ch) {
	return (ch == '\r') || (ch == '\n');
}

#define isSafeASCII(ch) ((unsigned int)(ch) <= 127)
// This one's redundant, but makes for more readable code
#define isHighBitChar(ch) ((unsigned int)(ch) > 127)

static inline bool isSafeAlpha(char ch) {
    return (isSafeASCII(ch) && isalpha(ch)) || ch == '_';
}

static inline bool isSafeAlnum(char ch) {
    return (isSafeASCII(ch) && isalnum(ch)) || ch == '_';
}

static inline bool isSafeAlnumOrHigh(char ch) {
    return isHighBitChar(ch) || isalnum(ch) || ch == '_';
}

static inline bool isSafeDigit(char ch) {
    return isSafeASCII(ch) && isdigit(ch);
}

static inline bool isSafeWordcharOrHigh(char ch) {
    // Error: scintilla's KeyWords.h includes '.' as a word-char
    // we want to separate things that can take methods from the
    // methods.
    return isHighBitChar(ch) || isalnum(ch) || ch == '_';
}

static bool inline iswhitespace(char ch) {
	return ch == ' ' || ch == '\t';
}

#define MAX_KEYWORD_LENGTH 200

#define STYLE_MASK 63
#define actual_style(style) (style & STYLE_MASK)

static bool followsDot(unsigned int pos, Accessor &styler) {
    styler.Flush();
    for (; pos >= 1; --pos) {
        int style = actual_style(styler.StyleAt(pos));
        char ch;
        switch (style) {
            case SCE_RB_DEFAULT:
                ch = styler[pos];
                if (ch == ' ' || ch == '\t') {
                    //continue
                } else {
                    return false;
                }
                break;
                
            case SCE_RB_OPERATOR:
                return styler[pos] == '.';

            default:
                return false;
        }
    }
    return false;
}

// Forward declarations
static bool keywordIsAmbiguous(const char *prevWord);
static bool keywordDoStartsLoop(int pos,
                                Accessor &styler);
static bool keywordIsModifier(const char *word,
                              int pos,
                              Accessor &styler);

static int ClassifyWordRb(unsigned int start, unsigned int end, WordList &keywords, Accessor &styler, char *prevWord) {
	char s[100];
    unsigned int i, j;
	unsigned int lim = end - start + 1; // num chars to copy
	if (lim >= MAX_KEYWORD_LENGTH) {
		lim = MAX_KEYWORD_LENGTH - 1;
	}
	for (i = start, j = 0; j < lim; i++, j++) {
		s[j] = styler[i];
	}
    s[j] = '\0';
	int chAttr;
	if (0 == strcmp(prevWord, "class"))
		chAttr = SCE_RB_CLASSNAME;
	else if (0 == strcmp(prevWord, "module"))
		chAttr = SCE_RB_MODULE_NAME;
	else if (0 == strcmp(prevWord, "def"))
		chAttr = SCE_RB_DEFNAME;
    else if (keywords.InList(s) && !followsDot(start - 1, styler)) {
        if (keywordIsAmbiguous(s)
            && keywordIsModifier(s, start, styler)) {
            
            // Demoted keywords are colored as keywords,
            // but do not affect changes in indentation.
            //
            // Consider the word 'if':
            // 1. <<if test ...>> : normal
            // 2. <<stmt if test>> : demoted
            // 3. <<lhs = if ...>> : normal: start a new indent level
            // 4. <<obj.if = 10>> : color as identifer, since it follows '.'
            
            chAttr = SCE_RB_WORD_DEMOTED;
        } else {
            chAttr = SCE_RB_WORD;
        }
	} else
        chAttr = SCE_RB_IDENTIFIER;
	styler.ColourTo(end, chAttr);
	if (chAttr == SCE_RB_WORD) {
		strcpy(prevWord, s);
	} else {
		prevWord[0] = 0;
	}
    return chAttr;
}


//XXX Identical to Perl, put in common area
static bool isMatch(Accessor &styler, int lengthDoc, int pos, const char *val) {
	if ((pos + static_cast<int>(strlen(val))) >= lengthDoc) {
		return false;
	}
	while (*val) {
		if (*val != styler[pos++]) {
			return false;
		}
		val++;
	}
	return true;
}

// Do Ruby better -- find the end of the line, work back,
// and then check for leading white space

// Precondition: the here-doc target can be indented
static bool lookingAtHereDocDelim(Accessor	   &styler,
                                  int 			pos,
                                  int 			lengthDoc,
                                  const char   *HereDocDelim)
{
    if (!isMatch(styler, lengthDoc, pos, HereDocDelim)) {
        return false;
    }
    while (--pos > 0) {
        char ch = styler[pos];
        if (isEOLChar(ch)) {
            return true;
        } else if (ch != ' ' && ch != '\t') {
            return false;
        }
    }
    return false;
}

//XXX Identical to Perl, put in common area
static char opposite(char ch) {
	if (ch == '(')
		return ')';
	if (ch == '[')
		return ']';
	if (ch == '{')
		return '}';
	if (ch == '<')
		return '>';
	return ch;
}

// Null transitions when we see we've reached the end
// and need to relex the curr char.

static void redo_char(int &i, char &ch, char &chNext, char &chNext2,
                      int &state) {
    i--;
    chNext2 = chNext;
    chNext = ch;
    state = SCE_RB_DEFAULT;
}

static void advance_char(int &i, char &ch, char &chNext, char &chNext2) {
    i++;
    ch = chNext;
    chNext = chNext2;
}

// precondition: startPos points to one after the EOL char
static bool currLineContainsHereDelims(int& startPos,
                                       Accessor &styler) {
    if (startPos <= 1)
        return false;

    int pos;
    for (pos = startPos - 1; pos > 0; pos--) {
        char ch = styler.SafeGetCharAt(pos);
        if (isEOLChar(ch)) {
            // Leave the pointers where they are -- there are no
            // here doc delims on the current line, even if
            // the EOL isn't default style
            
            return false;
        } else {
            styler.Flush();
            if (actual_style(styler.StyleAt(pos)) == SCE_RB_HERE_DELIM) {
                break;
            }
        }
    }
    if (pos == 0) {
        return false;
    }
    // Update the pointers so we don't have to re-analyze the string
    startPos = pos;
    return true;
}

// This class is used by the enter and exit methods, so it needs
// to be hoisted out of the function.

class QuoteCls {
    public:
    int  Count;
    char Up;
    char Down;
    QuoteCls() {
        this->New();
    }
    void New() {
        Count = 0;
        Up    = '\0';
        Down  = '\0';
    }
    void Open(char u) {
        Count++;
        Up    = u;
        Down  = opposite(Up);
    }
    QuoteCls(const QuoteCls& q) {
        // copy constructor -- use this for copying in
        Count = q.Count;
        Up    = q.Up;
        Down  = q.Down;
    }
    QuoteCls& operator=(const QuoteCls& q) { // assignment constructor
        if (this != &q) {
            Count = q.Count;
            Up    = q.Up;
            Down  = q.Down;
        }
		return *this;
    }
            
};


static void enterInnerExpression(int  *p_inner_string_types,
                                 int  *p_inner_expn_brace_counts,
                                 QuoteCls *p_inner_quotes,
                                 int&  inner_string_count,
                                 int&  state,
                                 int&  brace_counts,
                                 QuoteCls curr_quote
                                 ) {
    p_inner_string_types[inner_string_count] = state;
    state = SCE_RB_DEFAULT;
    p_inner_expn_brace_counts[inner_string_count] = brace_counts;
    brace_counts = 0;
    p_inner_quotes[inner_string_count] = curr_quote;
    ++inner_string_count;
}

static void exitInnerExpression(int *p_inner_string_types,
                                 int *p_inner_expn_brace_counts,
                                 QuoteCls *p_inner_quotes,
                                 int& inner_string_count,
                                 int& state,
                                 int&  brace_counts,
                                 QuoteCls& curr_quote
                                ) {
    --inner_string_count;
    state = p_inner_string_types[inner_string_count];
    brace_counts = p_inner_expn_brace_counts[inner_string_count];
    curr_quote = p_inner_quotes[inner_string_count];
}

static bool isEmptyLine(int pos,
                        Accessor &styler) {
	int spaceFlags = 0;
	int lineCurrent = styler.GetLine(pos);
	int indentCurrent = styler.IndentAmount(lineCurrent, &spaceFlags, NULL);
    return (indentCurrent & SC_FOLDLEVELWHITEFLAG) != 0;
}

static bool RE_CanFollowKeyword(const char *keyword) {
    if (!strcmp(keyword, "and")
        || !strcmp(keyword, "begin")
        || !strcmp(keyword, "break")
        || !strcmp(keyword, "case")
        || !strcmp(keyword, "do")
        || !strcmp(keyword, "else")
        || !strcmp(keyword, "elsif")
        || !strcmp(keyword, "if")
        || !strcmp(keyword, "next")
        || !strcmp(keyword, "return")
        || !strcmp(keyword, "when")
        || !strcmp(keyword, "unless")
        || !strcmp(keyword, "until")
        || !strcmp(keyword, "not")
        || !strcmp(keyword, "or")) {
        return true;
    }
    return false;
}

// Look at chars up to but not including endPos
// Don't look at styles in case we're looking forward