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-rw-r--r--src/core/utils/CSSParser.cpp45
-rw-r--r--src/core/utils/CSSParser.hpp3
-rw-r--r--src/core/utils/CodeTokenizer.cpp62
-rw-r--r--src/core/utils/CodeTokenizer.hpp57
-rw-r--r--src/core/utils/Tokenizer.cpp26
-rw-r--r--src/core/utils/Tokenizer.hpp122
6 files changed, 274 insertions, 41 deletions
diff --git a/src/core/utils/CSSParser.cpp b/src/core/utils/CSSParser.cpp
index e66eb34..1763cc2 100644
--- a/src/core/utils/CSSParser.cpp
+++ b/src/core/utils/CSSParser.cpp
@@ -17,6 +17,7 @@
*/
#include "BufferedCharReader.hpp"
+#include "CodeTokenizer.hpp"
#include "Tokenizer.hpp"
#include "CSSParser.hpp"
@@ -24,6 +25,7 @@
namespace ousia {
namespace utils {
+// CSS code tokens
static const int CURLY_OPEN = 1;
static const int CURLY_CLOSE = 2;
static const int COLON = 3;
@@ -31,8 +33,19 @@ static const int SEMICOLON = 4;
static const int HASH = 5;
static const int BRACKET_OPEN = 6;
static const int BRACKET_CLOSE = 7;
-static const int COMMENT_OPEN = 8;
-static const int COMMENT_CLOSE = 9;
+static const int PAREN_OPEN = 8;
+static const int PAREN_CLOSE = 9;
+// comments
+static const int COMMENT = 100;
+static const int COMMENT_OPEN = 101;
+static const int COMMENT_CLOSE = 102;
+// strings
+static const int STRING = 200;
+static const int SINGLE_QUOTE = 201;
+static const int DOUBLE_QUOTE = 202;
+static const int ESCAPE = 203;
+// general syntax
+static const int LINEBREAK = 300;
static const TokenTreeNode CSS_ROOT{{{"{", CURLY_OPEN},
{"}", CURLY_CLOSE},
@@ -41,16 +54,28 @@ static const TokenTreeNode CSS_ROOT{{{"{", CURLY_OPEN},
{"#", HASH},
{"[", BRACKET_OPEN},
{"]", BRACKET_CLOSE},
+ {"(", PAREN_OPEN},
+ {")", PAREN_CLOSE},
{"/*", COMMENT_OPEN},
- {"*/", COMMENT_CLOSE}}};
-
-StyleNode CSSParser::parse(BufferedCharReader &input) {
- Tokenizer tokenizer {input, CSS_ROOT};
- //TODO: implement
-
-}
-
+ {"*/", COMMENT_CLOSE},
+ {"\\", ESCAPE},
+ {"\''", SINGLE_QUOTE},
+ {"\"", DOUBLE_QUOTE},
+ {"\n", LINEBREAK}}};
+static const std::map<int, CodeTokenDescriptor> CSS_DESCRIPTORS = {
+ {COMMENT_OPEN, {CodeTokenMode::BLOCK_COMMENT_START, COMMENT}},
+ {COMMENT_CLOSE, {CodeTokenMode::BLOCK_COMMENT_END, COMMENT}},
+ {SINGLE_QUOTE, {CodeTokenMode::STRING_START_END, STRING}},
+ {DOUBLE_QUOTE, {CodeTokenMode::STRING_START_END, STRING}},
+ {ESCAPE, {CodeTokenMode::ESCAPE, ESCAPE}},
+ {LINEBREAK, {CodeTokenMode::LINEBREAK, LINEBREAK}}};
+StyleNode CSSParser::parse(BufferedCharReader &input)
+{
+ CodeTokenizer tokenizer{input, CSS_ROOT, CSS_DESCRIPTORS};
+ tokenizer.ignoreComments = true;
+ // TODO: implement
+}
}
}
diff --git a/src/core/utils/CSSParser.hpp b/src/core/utils/CSSParser.hpp
index 0f9cd8f..c8b772d 100644
--- a/src/core/utils/CSSParser.hpp
+++ b/src/core/utils/CSSParser.hpp
@@ -156,6 +156,9 @@ public:
};
class CSSParser {
+
+private:
+
public:
StyleNode parse(BufferedCharReader &input);
};
diff --git a/src/core/utils/CodeTokenizer.cpp b/src/core/utils/CodeTokenizer.cpp
index c1376af..e5b8610 100644
--- a/src/core/utils/CodeTokenizer.cpp
+++ b/src/core/utils/CodeTokenizer.cpp
@@ -23,30 +23,30 @@
namespace ousia {
namespace utils {
-Token CodeTokenizer::constructToken(const Token& t)
+Token CodeTokenizer::constructToken(const Token &t)
{
std::string content = buf.str();
buf.str(std::string());
- return Token{returnTokenId, content,
- startToken.startColumn, startToken.startLine,
- t.endColumn, t.endLine};
+ return Token{returnTokenId, content, startToken.startColumn,
+ startToken.startLine, t.endColumn, t.endLine};
}
void CodeTokenizer::buffer(const Token &t) { buf << t.content; }
bool CodeTokenizer::doPrepare(const Token &t, std::deque<Token> &peeked)
{
- if (t.startLine != t.endLine) {
- throw TokenizerException(
- "We did not expect a multiline token. Most likely you did not add "
- "a linebreak token to your tokenizer!");
- }
-
auto it = descriptors.find(t.tokenId);
CodeTokenMode mode = CodeTokenMode::NONE;
if (it != descriptors.end()) {
mode = it->second.mode;
}
+
+ if (t.startLine != t.endLine && mode != CodeTokenMode::LINEBREAK) {
+ throw TokenizerException(
+ "We did not expect a multiline token (except linebreaks). Most "
+ "likely you did not add a linebreak token to your tokenizer!");
+ }
+
switch (state) {
case CodeTokenizerState::NORMAL:
switch (mode) {
@@ -59,25 +59,47 @@ bool CodeTokenizer::doPrepare(const Token &t, std::deque<Token> &peeked)
case CodeTokenMode::LINE_COMMENT:
state = CodeTokenizerState::IN_LINE_COMMENT;
break;
+ case CodeTokenMode::LINEBREAK:
+ peeked.push_back({it->second.id, t.content, t.startColumn,
+ t.startLine, t.endColumn, t.endLine});
+ return true;
default:
if (t.tokenId == TOKEN_TEXT) {
int begin = -1;
for (size_t c = 0; c < t.content.length(); c++) {
bool isWhitespace =
t.content[c] == ' ' || t.content[c] == '\t';
- if (begin >= 0 && isWhitespace) {
- peeked.push_back(Token{
- TOKEN_TEXT,
- t.content.substr(begin, (int)c - begin),
- t.startColumn + begin, t.startLine,
- t.startColumn + (int)c, t.endLine});
- }
- if (!isWhitespace && begin < 0) {
- begin = c;
+ if (begin < 0) {
+ // if we have not yet set our beginning,
+ // we wait for the first
+ // non-whitespace-character to set it.
+ if (!isWhitespace) {
+ begin = c;
+ }
+ } else {
+ // if we have set our beginning, we wait for the
+ // first whitespace character, which marks the
+ // end of the current word.
+ if (isWhitespace) {
+ peeked.push_back(Token{
+ TOKEN_TEXT,
+ t.content.substr(begin, (int)c - begin),
+ t.startColumn + begin, t.startLine,
+ t.startColumn + (int)c, t.endLine});
+ begin = -1;
+ }
}
}
+ if(begin >= 0){
+ peeked.push_back(Token{
+ TOKEN_TEXT,
+ t.content.substr(begin),
+ t.startColumn + begin, t.startLine,
+ t.endColumn, t.endLine});
+ }
+ } else {
+ peeked.push_back(t);
}
- peeked.push_back(t);
return true;
}
startToken = t;
diff --git a/src/core/utils/CodeTokenizer.hpp b/src/core/utils/CodeTokenizer.hpp
index f26a74c..0fc0862 100644
--- a/src/core/utils/CodeTokenizer.hpp
+++ b/src/core/utils/CodeTokenizer.hpp
@@ -28,6 +28,17 @@
namespace ousia {
namespace utils {
+/*
+ * This enum contains all special Token the CodeTokenizer supports, namely:
+ *
+ * 1.) An ambigous Tokens - in post programming languages single-quotes ' or
+ * double-quotes " - to delimit string tokens.
+ * 2.) A start token for line comments, which would e.g. be // in Java.
+ * 3.) A start token for a block comment
+ * 4.) An end token for a block comment.
+ * 5.) A linebreak token
+ * 6.) The escape token, which would e.g. be \ in java.
+ */
enum class CodeTokenMode {
STRING_START_END,
LINE_COMMENT,
@@ -38,6 +49,12 @@ enum class CodeTokenMode {
NONE
};
+/**
+ * A CodeTokenDescriptor defines the id the user likes to have returned for
+ * a Token of the mode specified, e.g. if you want to get the id 4 for a
+ * String Token the corresponding CodeTokenDescriptor would be inizialized
+ * with CodeTokenDescriptor myDesc {CodeTokenMode::STRING_START_END, 4};
+ */
struct CodeTokenDescriptor {
CodeTokenMode mode;
int id;
@@ -45,7 +62,10 @@ struct CodeTokenDescriptor {
CodeTokenDescriptor(CodeTokenMode mode, int id) : mode(mode), id(id) {}
};
-
+/**
+ * The CodeTokenizer is a finite state machine with the states NORMAL, being
+ * IN_BLOCK_COMMENT, being IN_LINE_COMMENT or being IN_STRING.
+ */
enum class CodeTokenizerState {
NORMAL,
IN_BLOCK_COMMENT,
@@ -53,6 +73,14 @@ enum class CodeTokenizerState {
IN_STRING
};
+/**
+ * The purpose of a CodeTokenizer is to make it easier to parse classical
+ * programming Code. It adds the following features to a regular Tokenizer:
+ * 1.) String tokens (e.g. "string" in Java Code) instead of 3 separate tokens
+ * for the opening delimiter, the text and the closing delimiter.
+ * 2.) Escaping in String tokens.
+ * 3.) Comment Tokens (for line comments as well as block comments)
+ */
class CodeTokenizer : public Tokenizer {
private:
std::map<int, CodeTokenDescriptor> descriptors;
@@ -62,18 +90,37 @@ private:
int returnTokenId;
bool escaped = false;
- Token constructToken(const Token& t);
- void buffer(const Token& t);
+ Token constructToken(const Token &t);
+ void buffer(const Token &t);
protected:
bool doPrepare(const Token &t, std::deque<Token> &peeked) override;
public:
+ /**
+ * If you do not want comment tokens to be returned you can set this to
+ * true.
+ */
bool ignoreComments = false;
+ /**
+ *
+ * @param input a BufferedCharReader containing the input for this
+ *tokenizer,
+ * as with a regular tokenizer.
+ * @param root a TokenTreeNode representing the root of the TokenTree.
+ * Please note that you have to specify all tokenIDs here that you use
+ * in the descriptors map.
+ * @param descriptors a map mapping tokenIDs to CodeTokenDescriptors.
+ * In this way you can specify the meaning of certain Tokens. Say you
+ * specified the Token "//" with the id 1 in the TokenTree. Then you could
+ * add the entry "1" with the Mode "LINE_COMMENT" to the descriptors map
+ * and this CodeTokenizer would recognize the token "//" as starting a
+ * line comment.
+ */
CodeTokenizer(BufferedCharReader &input, const TokenTreeNode &root,
- std::map<int, CodeTokenDescriptor> descriptors)
- : Tokenizer(input, root), descriptors(descriptors)
+ std::map<int, CodeTokenDescriptor> descriptors)
+ : Tokenizer(input, root), descriptors(descriptors), state(CodeTokenizerState::NORMAL)
{
}
};
diff --git a/src/core/utils/Tokenizer.cpp b/src/core/utils/Tokenizer.cpp
index 164a30f..a0ca3aa 100644
--- a/src/core/utils/Tokenizer.cpp
+++ b/src/core/utils/Tokenizer.cpp
@@ -82,8 +82,8 @@ bool Tokenizer::prepare()
{
std::stringstream buffer;
char c;
- const int startColumn = input.getColumn();
- const int startLine = input.getLine();
+ int startColumn = input.getColumn();
+ int startLine = input.getLine();
bool bufEmpty = true;
while (input.peek(&c)) {
if (root.children.find(c) != root.children.end()) {
@@ -118,9 +118,10 @@ bool Tokenizer::prepare()
break;
}
}
+ //reset the peek pointer to the last valid position.
+ input.resetPeek();
// check if we did indeed find a special token.
if (match != TOKEN_NONE) {
- input.resetPeek();
if (bufEmpty) {
// if we did not have text before, construct that token.
if (doPrepare(
@@ -128,8 +129,11 @@ bool Tokenizer::prepare()
input.getColumn(), input.getLine()},
peeked)) {
return true;
+ } else {
+ startColumn = input.getColumn();
+ startLine = input.getLine();
+ continue;
}
-
} else {
// otherwise we return the text before the token.
if (doPrepare(Token{TOKEN_TEXT, buffer.str(), startColumn,
@@ -137,8 +141,20 @@ bool Tokenizer::prepare()
input.getLine()},
peeked)) {
return true;
- }
+ } else{
+ //we need to clear the buffer here. After all the token
+ //corresponding to this buffer segment is already
+ //constructed.
+ buffer.str(std::string());
+ bufEmpty = true;
+ startColumn = input.getColumn();
+ startLine = input.getLine();
+ continue;
+ }
}
+ } else{
+ //if we found nothing, read at least one character.
+ input.peek(&c);
}
}
buffer << c;
diff --git a/src/core/utils/Tokenizer.hpp b/src/core/utils/Tokenizer.hpp
index eb8eed4..2debc75 100644
--- a/src/core/utils/Tokenizer.hpp
+++ b/src/core/utils/Tokenizer.hpp
@@ -28,6 +28,11 @@
namespace ousia {
namespace utils {
+/**
+ * This exception is currently only thrown if errors are made during the
+ * initialization of the Tokenizer. Have a closer look at the documentation
+ * of the TokenTreeNode constructor for more information.
+ */
class TokenizerException : public std::exception {
public:
const std::string msg;
@@ -37,17 +42,82 @@ public:
virtual const char *what() const noexcept override { return msg.c_str(); }
};
+/**
+ * The Tokenizer internally uses a TokenTree to be efficiently able to identify
+ * the longest consecutive token in the text. This is equivalent to a prefix
+ * trie.
+ *
+ * The TokenTree is a construct that structures all special tokens this
+ * Tokenizer recognizes. Consider the Tokens "aab", "a" and "aac". Then
+ * the TokenTree would look like this:
+ *
+ * a
+ * | \
+ * a $
+ * | \
+ * b c
+ * | |
+ * $ $
+ *
+ * Every node in the TokenTree is a valid end state that has a $ attached to it.
+ * During the search algorithm the Tokenizer goes through the tree and stores
+ * the last valid position. If a character follows that does not lead to a new
+ * node in the TokenTree the search ends (and starts again at this character).
+ * The token corresponding to the last valid position is returned.
+ *
+ * This allows us to uniquely identify the matching token given a certain
+ * input text. Note that this is a greedy matching approach that does not
+ * work if you're using truly ambiguous tokens (that have the same text).
+ *
+ * It is also not allowed that tokens have common middle parts but varying
+ * pre- and suffixes. Consider the example of two tokens "abd" and "bc" and
+ * the input string "abc". In that case we start looking for "abd" at the
+ * start, won't find it, wenn we hit "c" and start the scanning process
+ * anew. Thus the "bc" token is not found.
+ *
+ * For most (well-behaved) tokenization schemes this is not the case,
+ * though.
+ */
class TokenTreeNode {
public:
const std::map<char, TokenTreeNode> children;
const int tokenId;
+ /**
+ * The TokenTreeNode constructor builds a TokenTree from the given token
+ * specifications. The node returned by this constructor then is the root of
+ * said TokenTree.
+ * @param inputs Specifications of tokens in map form. Each specification
+ * is a tuple of the text that should be matched and some unique ID (>= 0)
+ * that is returned to you if that Token is found in the text.
+ * An example for such a map would be
+ * {
+ * { "#" , 1},
+ * { "##", 2},
+ * { "/" , 3}
+ * }
+ * Note that IDs below zero are reserved for system Ids, mainly TOKEN_NONE
+ * (-1) and TOKEN_TEXT (-2).
+ */
TokenTreeNode(const std::map<std::string, int> &inputs);
};
+/**
+ * This is a reserved constant for the empty token.
+ */
static const int TOKEN_NONE = -1;
+/**
+ * This is a reserved constant for every part of the input text that is not a
+ * specified token.
+ */
static const int TOKEN_TEXT = -2;
+/**
+ * A token for us is identified by an integer tokenID (either one of the
+ * constants TOKEN_NONE or TOKEN_TEXT or one of the user-defined constants).
+ * Additionally we return the matched text (which should only be really
+ * interesting in case of TOKEN_TEXT tokens) and the position in the input text.
+ */
struct Token {
int tokenId;
std::string content;
@@ -70,6 +140,25 @@ struct Token {
Token() : tokenId(TOKEN_NONE) {}
};
+/**
+ * A Tokenizer has the purpose of subdividing an input text into tokens. In our
+ * definition here we distinguish between two kinds of tokens:
+ * 1.) User-specified tokens that match a fixed text.
+ * 2.) Any other text between those tokens.
+ * The user might want to specify the tokens '#{' and '#}' for example, because
+ * they have some meaning in her code. The user sets the IDs to 1 and 2.
+ * Given the input text
+ * "some text #{ special command #} some text"
+ * the tokenizer would return the tokens:
+ * 1.) "some text " with the id TOKEN_TEXT (-2).
+ * 2.) "#{" with the id 1.
+ * 3.) " special command " with the id TOKEN_TEXT (-2).
+ * 4.) "#}" with the id 2.
+ * 5.) " some text" with the id TOKEN_TEXT (-2).
+ * This makes the subsequent parsing of files of a specific type easier.
+ * Note that in case of tokens with that are prefixes of other tokens the
+ * longest possible match is returned.
+ */
class Tokenizer {
private:
BufferedCharReader &input;
@@ -95,14 +184,45 @@ protected:
virtual bool doPrepare(const Token &t, std::deque<Token> &peeked);
public:
+ /**
+ * @param input The input of a Tokenizer is given in the form of a
+ * BufferedCharReader. Please refer to the respective documentation.
+ * @param root This is meant to be the root of a TokenTree giving the
+ * specification of user-defined tokens this Tokenizer should recognize.
+ * The Tokenizer promises to not change the TokenTree such that you can
+ * re-use the same specification for multiple inputs.
+ * Please refer to the TokenTreeNode documentation for more information.
+ */
Tokenizer(BufferedCharReader &input, const TokenTreeNode &root);
+ /**
+ * The next method consumes one Token from the input stream and gives
+ * it to the user (stored in the input argument).
+ *
+ * @param t a Token reference that is set to the next found token.
+ * @return true if a next token was found and false if the input is at its
+ * end.
+ */
bool next(Token &t);
-
+ /**
+ * The peek method does not consume the next Token but buffers it and
+ * shows it to the user (stored in the input argument).
+ *
+ * @param t a Token reference that is set to the next found token.
+ * @return true if a next token was found and false if the input is at its
+ * end.
+ */
bool peek(Token &t);
+ /**
+ * Resets the peek pointer to the current position in the stream (to the
+ * beginning of the buffer).
+ */
void resetPeek();
+ /**
+ * Clears the peek buffer, such that all peeked Tokens are consumed.
+ */
void consumePeek();
};
}
generated by cgit v1.2.3 (git 2.39.1) at 2025-05-01 07:19:05 +0000