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magicseteditor
Commit 9e911419 authored by twanvl's avatar twanvl
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better script parser with respect to newlines

parent 2e870711
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Showing with 120 additions and 140 deletions
src/script/parser.cpp
View file @ 9e911419
......@@ -27,7 +27,7 @@ enum TokenType
, TOK_OPER // + - * / . ;
, TOK_LPAREN // ( { [
, TOK_RPAREN // ) } ]
, TOK_NEWLINE // newline
, TOK_DUMMY // placeholder for putBack
, TOK_EOF // end of input
};
......@@ -35,6 +35,7 @@ enum TokenType
struct Token {
TokenType type;
String value;
bool newline; ///< Is there a newline between this token and the previous one?
inline operator == (TokenType t) const { return type == t; }
inline operator != (TokenType t) const { return type != t; }
......@@ -65,10 +66,13 @@ class TokenIterator {
size_t pos;
vector<Token> buffer; // buffer of unread tokens, front() = current
stack<bool> open_braces; // braces we entered, true if the brace was from a smart string escape
bool newline; ///< Did we just pass a newline?
/// Add a token to the buffer, with the current newline value, resets newline
void addToken(TokenType type, const String& value);
/// Read the next token, and add it to the buffer
void addToken();
void readToken();
/// Read the next token which is a string (after the opening ")
void addStringToken();
void readStringToken();
};
// ----------------------------------------------------------------------------- : Characters
......@@ -92,7 +96,7 @@ TokenIterator::TokenIterator(const String& str)
const Token& TokenIterator::peek(size_t offset) {
// read the next token until we have enough
while (buffer.size() <= offset) {
addToken();
readToken();
}
return buffer[offset];
}
......@@ -103,71 +107,70 @@ const Token& TokenIterator::read() {
}
void TokenIterator::putBack() {
Token t = {TOK_NEWLINE, _("\n")};
// Don't use addToken, because it canges newline
// Also, we want to push_front
Token t = {TOK_DUMMY, _(""), false};
buffer.insert(buffer.begin(), t);
}
void TokenIterator::addToken() {
void TokenIterator::addToken(TokenType type, const String& value) {
Token t = {type, value, newline};
buffer.push_back(t);
newline = false;
}
void TokenIterator::readToken() {
if (pos >= input.size()) {
// EOF
Token t = {TOK_EOF, _("end of input")};
buffer.push_back(t);
addToken(TOK_EOF, _("end of input"));
return;
}
// read a character from the input
Char c = input.GetChar(pos++);
if (c == _('\n')) {
Token t = {TOK_NEWLINE, _("newline")};
buffer.push_back(t);
newline = true;
} else if (isSpace(c)) {
// ignore
} else if (isAlpha(c)) {
// name
size_t start = pos - 1;
while (pos < input.size() && isAlnum_(input.GetChar(pos))) ++pos;
Token t = {TOK_NAME, cannocial_name_form(input.substr(start, pos-start)) }; // convert name to cannocial form
buffer.push_back(t);
addToken(TOK_NAME, cannocial_name_form(input.substr(start, pos-start))); // convert name to cannocial form
} else if (isDigit(c)) {
// number
size_t start = pos - 1;
while (pos < input.size() && isDigitOrDot(input.GetChar(pos))) ++pos;
String num = input.substr(start, pos-start);
Token t = {
addToken(
num.find_first_of('.') == String::npos ? TOK_INT : TOK_DOUBLE,
num
};
buffer.push_back(t);
);
} else if (isOper(c)) {
// operator
Token t = { TOK_OPER };
if (pos < input.size() && isLongOper(input.substr(pos - 1, 2))) {
// long operator
t.value = input.substr(pos - 1, 2);
addToken(TOK_OPER, input.substr(pos - 1, 2));
pos += 1;
} else {
t.value = input.substr(pos - 1, 1);
addToken(TOK_OPER, input.substr(pos - 1, 1));
}
buffer.push_back(t);
} else if (c==_('"')) {
// string
addStringToken();
readStringToken();
} else if (c == _('}') && !open_braces.empty() && open_braces.top()) {
// closing smart string, resume to string parsing
// "a{e}b" --> "a" "{ e }" "b"
open_braces.pop();
Token t2 = {TOK_RPAREN, _("}\"")};
buffer.push_back(t2);
addStringToken();
addToken(TOK_RPAREN, _("}\""));
readStringToken();
} else if (isLparen(c)) {
// paranthesis/brace
open_braces.push(false);
Token t = { TOK_LPAREN, String(1,c) };
buffer.push_back(t);
addToken(TOK_LPAREN, String(1,c));
} else if (isRparen(c)) {
// paranthesis/brace
if (!open_braces.empty()) open_braces.pop();
Token t = { TOK_RPAREN, String(1,c) };
buffer.push_back(t);
addToken(TOK_RPAREN, String(1,c));
} else if(c==_('#')) {
// comment untill end of line
while (pos < input.size() && input[pos] != _('\n')) ++pos;
......@@ -176,33 +179,32 @@ void TokenIterator::addToken() {
}
}
void TokenIterator::addStringToken() {
Token t = {TOK_STRING};
void TokenIterator::readStringToken() {
String str;
while (true) {
if (pos >= input.size()) throw ScriptParseError(_("Unexpected end of input in string constant"));
Char c = input[pos++]; //% input.GetChar(pos++);
// parse the string constant
if (c == _('"')) {
// end of string
buffer.push_back(t);
addToken(TOK_STRING, str);
return;
} else if (c == _('\\')) {
// escape
if (pos >= input.size()) throw ScriptParseError(_("Unexpected end of input in string constant"));
c = input[pos++];
if (c == _('n')) t.value += _('\n');
if (c == _('<')) t.value += _('\1'); // escape for <
else t.value += c; // \ or { or "
if (c == _('n')) str += _('\n');
if (c == _('<')) str += _('\1'); // escape for <
else str += c; // \ or { or "
} else if (c == _('{')) {
// smart string
// "a{e}b" --> "a" "{ e }" "b"
buffer.push_back(t);
addToken(TOK_STRING, str);
open_braces.push(true);
Token t2 = {TOK_LPAREN, _("\"{")};
buffer.push_back(t2);
addToken(TOK_LPAREN, _("\"{"));
return;
} else {
t.value += c;
str += c;
}
}
}
......@@ -257,7 +259,6 @@ ScriptP parse(const String& s) {
// Expect a token, throws if it is not found
void expectToken(TokenIterator& input, const Char* expect) {
Token token = input.read();
while (token == TOK_NEWLINE) token = input.read(); // skip newlines
if (token != expect) {
throw ScriptParseError(expect, token.value);
}
......@@ -371,8 +372,6 @@ void parseExpr(TokenIterator& input, Script& script, Precedence minPrec) {
script.addInstruction(I_PUSH_CONST, toScript(d));
} else if (token == TOK_STRING) {
script.addInstruction(I_PUSH_CONST, toScript(token.value));
} else if (token == TOK_NEWLINE) {
continue; // ignore
} else {
throw ScriptParseError(_("Unexpected token '") + token.value + _("'"));
}
......@@ -382,15 +381,16 @@ void parseExpr(TokenIterator& input, Script& script, Precedence minPrec) {
void parseOper(TokenIterator& input, Script& script, Precedence minPrec, InstructionType closeWith, int closeWithData) {
parseExpr(input, script, minPrec); // first argument
bool newlines = false; // did we skip any newlines?
// read any operators after an expression
// EBNF: expr = expr | expr oper expr
// without left recursion: expr = expr (oper expr)*
while (true) {
const Token& token = input.read();
bool newlines2 = newlines;
newlines = false;
if (token == TOK_OPER || token == TOK_NAME) {
if (token != TOK_OPER && token != TOK_NAME && token!=TOK_LPAREN) {
// not an operator-like token
input.putBack();
break;
}
if (minPrec <= PREC_SEQ && token==_(";")) {
Token next = input.peek(1);
if (next == TOK_RPAREN || next == TOK_EOF) {
......@@ -431,13 +431,10 @@ void parseOper(TokenIterator& input, Script& script, Precedence minPrec, Instruc
} else {
throw ScriptParseError(_("name"), input.peek().value);
}
} else {
input.putBack();
newlines = newlines2; // remember newlines
break; // unknown operator
}
} else if (token==TOK_LPAREN) {
if (minPrec <= PREC_FUN && token==_("(")) {
} else if (minPrec <= PREC_FUN && token==_("[")) { // get member by expr
parseOper(input, script, PREC_ALL, I_BINARY, I_MEMBER);
expectToken(input, _("]"));
} else if (minPrec <= PREC_FUN && token==_("(")) {
// function call, read arguments
vector<int> arguments;
Token t = input.peek();
......@@ -466,39 +463,22 @@ void parseOper(TokenIterator& input, Script& script, Precedence minPrec, Instruc
FOR_EACH(arg,arguments) {
script.addInstruction(I_NOP, arg);
}
} else if (minPrec <= PREC_FUN && token==_("[")) { // get member by expr
parseOper(input, script, PREC_ALL, I_BINARY, I_MEMBER);
expectToken(input, _("]"));
} else if (minPrec <= PREC_STRING && token==_("\"{")) {
// for smart strings: "x" {{ e }} "y"
parseOper(input, script, PREC_ALL, I_BINARY, I_ADD); // e
expectToken(input, _("}\""));
parseOper(input, script, PREC_NONE, I_BINARY, I_ADD); // y
} else {
} else if (minPrec <= PREC_NEWLINE && token.newline) {
// newline functions as ;
// only if we don't match another token!
input.putBack();
newlines = newlines2; // remember newlines
break; // unknown LPAREN, has to be {
}
} else if (token == TOK_NEWLINE) {
const Token& next = input.peek(1);
if (minPrec <= PREC_NEWLINE && (next == TOK_NAME || next == TOK_LPAREN)) {
// function as ;
script.addInstruction(I_POP);
parseOper(input, script, PREC_SET);
} else {
// skip newlines
newlines = true;
}
} else {
input.putBack();
newlines = newlines2; // remember newlines
break;
}
}
if (newlines) {
// we accidentally ate a newline, restore it
input.putBack();
}
// add closing instruction
if (closeWith != I_NOP) {
script.addInstruction(closeWith, closeWithData);
......
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