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lexer.d
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lexer.d
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// Written in the D programming language
// Author: Timon Gehr
// License: http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0
import std.string, utf = std.utf, std.uni;
import std.stdio, std.conv;
import std.algorithm : startsWith, swap;
import std.traits : EnumMembers;
import core.memory;
import util : lowerf, escape, mallocAppender, toEngNum;
mixin("enum TokenType{"~TokenNames()~"}");
template Tok(string type){mixin(TokImpl());}
template TokChars(TokenType type){mixin(TokCharsImpl());}
private immutable {
string[2][] complexTokens =
[["i", "Identifier" ],
["``", "StringLiteral" ],
["``c", "StringLiteralC" ],
["``w", "StringLiteralW" ],
["``d", "StringLiteralD" ],
["' '", "CharacterLiteral" ],
["0", "IntLiteral" ],
["0U", "UintLiteral" ],
["0L", "LongLiteral" ],
["0LU", "UlongLiteral" ],
[".0f", "FloatLiteral" ],
[".0", "DoubleLiteral" ],
[".0L", "RealLiteral" ],
[".0fi", "ImaginaryFloatLiteral" ],
[".0i", "ImaginaryDoubleLiteral" ],
[".0Li", "ImaginaryLiteral" ]];
string[2][] simpleTokens =
[["/", "Divide" ],
["/=", "DivideAssign" ],
[".", "Dot" ],
["..", "DotDot" ],
["...", "DotDotDot" ],
["&", "And" ],
["&=", "AndAssign" ],
["&&", "AndAnd" ],
["|", "Or" ],
["|=", "OrAssign" ],
["||", "OrOr" ],
["-", "Minus" ],
["-=", "MinusAssign" ],
["--", "MinusMinus" ],
["+", "Plus" ],
["+=", "PlusAssign" ],
["++", "PlusPlus" ],
["<", "Less" ],
["<=", "LessEqual" ],
["<<", "LeftShift" ],
["<<=", "LeftShiftAssign" ],
["<>", "LessGreater" ],
["<>=", "LessGreaterEqual" ],
[">", "Greater" ],
[">=", "GreaterEqual" ],
[">>=", "RightShiftAssign" ],
[">>>=", "LogicalRightShiftAssign" ],
[">>", "RightShift" ],
[">>>", "LogicalRightShift" ],
["!", "ExclamationMark" ],
["!=", "NotEqual" ],
["!<>", "NotLessGreater" ],
["!<>=", "Unordered" ],
["!<", "NotLess" ],
["!<=", "NotLessEqual" ],
["!>", "NotGreater" ],
["!>=", "NotGreaterEqual" ],
["(", "LeftParen" ],
[")", "RightParen" ],
["[", "LeftBracket" ],
["]", "RightBracket" ],
["{", "LeftCurly" ],
["}", "RightCurly" ],
["?", "QuestionMark" ],
[",", "Comma" ],
[";", "Semicolon" ],
[":", "Colon" ],
["$", "Dollar" ],
["=", "Assign" ],
["=>", "GoesTo" ],
["==", "Equal" ],
["*", "Star" ],
["*=", "MultiplyAssign" ],
["%", "Modulo" ],
["%=", "ModuloAssign" ],
["^", "Xor" ],
["^=", "XorAssign" ],
["^^", "Pow" ],
["^^=", "PowAssign" ],
["~", "Concat" ],
["~=", "ConcatAssign" ],
["@", "At" ]];
string[2][] specialTokens =
[["", "None", ],
[" ", "Whitespace", ],
["//", "Comment", ],
["///", "DokComment", ],
["\n", "NewLine", ], // TODO: incorporate unicode new line support
["Error", "Error" ],
["__error","ErrorLiteral" ],
["EOF", "Eof" ]];
string[2][] compoundTokens =
[["auto ref", "AutoRef" ],
["!is" , "NotIs" ],
["!in" , "NotIn" ]];
string[] keywords = ["abstract", "alias", "align", "asm", "assert", "auto", "body", "bool", "break", "byte", "case", "cast", "catch", "cdouble", "cent", "cfloat", "char", "class", "const", "continue", "creal", "dchar", "debug", "default", "delegate", "delete", "deprecated", "do", "double", "else", "enum", "export", "extern", "false", "final", "finally", "float", "for", "foreach", "foreach_reverse", "function", "goto", "idouble", "if", "ifloat", "immutable", "import", "in", "inout", "int", "interface", "invariant", "ireal", "is", "lazy", "long", "macro", "mixin", "module", "new", "nothrow", "null", "out", "override", "package", "pragma", "private", "protected", "public", "pure", "real", "ref", "return", "scope", "shared", "short", "static", "struct", "super", "switch", "synchronized", "template", "this", "throw", "true", "try", "typedef", "typeid", "typeof", "ubyte", "ucent", "uint", "ulong", "union", "unittest", "ushort", "version", "void", "volatile", "wchar", "while", "with", /*"__FILE__", "__LINE__",*/ "__gshared", "__thread", "__traits"];
string[2][] tokens = specialTokens ~ complexTokens ~ simpleTokens ~ compoundTokens ~ keywordTokens();
}
private{
auto keywordTokens(){
immutable(string[2])[] r;
foreach(i,kw;keywords) r~=[kw,kw~"_"];
return r;
}
string TokenNames(){
string r;
foreach(t;tokens) r~=lowerf(t[1])~",";
return r;
}
string TokImpl(){
string r="static if(type==\""~tokens[0][0]~"\") alias TokenType."~lowerf(tokens[0][1])~" Tok;";
foreach(t;tokens) r~="else static if(type==\""~t[0]~"\") alias TokenType."~lowerf(t[1])~" Tok;";
r~="else static assert(0,\"unknown Token '\"~type~\"'\");";
return r;
}
string TokCharsImpl(){
string r="static if(type==TokenType."~lowerf(tokens[0][1])~") enum TokChars=\""~tokens[0][0]~"\";";
foreach(t;tokens) r~="else static if(type==TokenType."~lowerf(t[1])~") enum TokChars=\""~t[0]~"\";";
r~="else static assert(0,\"invalid TokenType \"~to!string(type));";
return r;
}
}
string TokenTypeToString(TokenType type){
return tokens[cast(int)type][0];
}
string toString(immutable(Token)[] a){string r;foreach(t;a) r~='['~t.toString()~']'; return r;}
class Source{
immutable{
string name;
string code;
}
this(string name, string code)in{auto c=code;assert(c.length>=4&&!c[$-4]&&!c[$-3]&&!c[$-2]&&!c[$-1]);}body{ // four padding zero bytes required because of UTF{
this.name = name;
this.code = code[0..$-4]; // don't expose the padding zeros
sources ~= this;
}
string getLineOf(string rep)in{assert(this is get(rep));}body{
//if(!code.length) return code;
string before=code.ptr[0..code.length+4][0..rep.ptr-code.ptr];
string after =code.ptr[0..code.length+4][rep.ptr-code.ptr..$];
immutable(char)* start=code.ptr, end=code.ptr+code.length;
foreach_reverse(ref c; before) if(c=='\n'||c=='\r'){start = &c+1; break;}
foreach(ref c; after) if(c=='\n'||c=='\r'){end = &c; break;}
return start[0..end-start];
}
static Source get(string rep){
foreach(x; sources) if(rep.ptr>=x.code.ptr && rep.ptr+rep.length<=x.code.ptr+x.code.length+4) return x;
return null;
}
void dispose(){
foreach(i,x; sources) if(x is this){
swap(sources[i], sources[$-1]);
sources=sources[0..$-1];
sources.assumeSafeAppend();
return;
}
assert(0);
}
private static Source[] sources;
}
struct Location{
string rep; // slice of the code representing the Location
int line; // line number at start of location
// reference to the source the code belongs to
@property Source source()const{
auto src = Source.get(rep);
assert(src, "source for '"~rep~"' not found!");
return src;
}
Location to(const(Location) end)const{// in{assert(end.source is source);}body{
// in{assert(rep.ptr<=end.rep.ptr);}body{ // requiring that is not robust enough
if(rep.ptr>end.rep.ptr+end.rep.length) return cast()this;
return Location(rep.ptr[0..end.rep.ptr-rep.ptr+end.rep.length],line);
}
}
import std.array;
int getColumn(Location loc, int tabsize){
int res=0;
auto l=loc.source.getLineOf(loc.rep);
for(;!l.empty&&l[0]&&l.ptr<loc.rep.ptr; l.popFront()){
if(l.front=='\t') res=res-res%tabsize+tabsize;
else res++;
}
return res+1;
}
struct Token{
TokenType type;
string toString() const{
if(type == Tok!"EOF") return "EOF";
if(loc.rep.length) return loc.rep;
// TODO: remove boilerplate
// TODO: get better representations
switch(type){
case Tok!"i":
return name;
case Tok!"``":
return '"'~escape(str)~'"';
case Tok!"``c":
return '"'~escape(str)~`"c`;
case Tok!"``w":
return '"'~escape(str)~`"w`;
case Tok!"``d":
return '"'~escape(str)~`"d`;
case Tok!"' '":
return '\''~escape(to!string(cast(dchar)int64),false)~'\'';
case Tok!"0":
return to!string(cast(int)int64);
case Tok!"0U":
return to!string(cast(uint)int64)~'U';
case Tok!"0L":
return to!string(cast(long)int64)~'L';
case Tok!"0LU":
return to!string(int64)~"LU";
case Tok!".0f":
return to!string(flt80)~'f';
case Tok!".0":
return to!string(flt80);
case Tok!".0L":
return to!string(flt80)~'L';
case Tok!".0i":
return to!string(flt80)~'i';
case Tok!".0fi":
return to!string(flt80)~"fi";
case Tok!".0Li":
return to!string(flt80)~"Li";
case Tok!"Error":
return "error: "~str;
default:
return tokens[cast(int)type][0];case Tok!"true": return "true";
}
}
union{
string str, name; // string literals, identifiers
ulong int64; // integer literals
real flt80; // float, double, real literals
}
Location loc;
}
template token(string t){enum token=Token(Tok!t);} // unions not yet supported
unittest{
static assert({
foreach(i;simpleTokens){
string s=i[0];
bool found = s.length==1;
foreach(j;simpleTokens) if(j[0] == s[0..$-1]) found = true;
if(!found) return false;
}return true;
}(),"Every non-empty prefix of simpleTokens must be a valid token.");
}
string caseSimpleToken(string prefix="", bool needs = false)pure{
string r;
int c=0,d=0;
foreach(i;simpleTokens){string s=i[0]; if(s.startsWith(prefix)) c++;}
if(c==1) r~=`res[0].type = Tok!"`~prefix~'"'~";\nbreak;\n";
else{
if(needs) r~="switch(*p){\n";
foreach(i;simpleTokens){
string s = i[0]; if(s[0]=='/' || s[0] == '.') continue; // / can be the start of a comment, . could be the start of a float literal
if(s.startsWith(prefix) && s.length==prefix.length+1){
r~=`case '`~s[$-1]~"':\n"~(needs?"p++;\n":"");
r~=caseSimpleToken(s,true);
}
}
if(prefix=="!") r~="default: mixin(lexNotAndNotIsAndNotIn);\nbreak;\n}\nbreak;\n";
else if(needs) r~=`default: res[0].type = Tok!"`~prefix~`"`~";\nbreak;\n}\nbreak;\n";
}
return r;
}
auto lex(Source source){ // pure
return Lexer(source);
}
struct Anchor{
size_t index;
}
struct Lexer{
string code; // Manually allocated!
Token[] buffer;
Token[] errors;
Source source;
size_t n,m; // start and end index in buffer
size_t s,e; // global start and end index
size_t numAnchors; // number of existing anchors for this lexer
size_t firstAnchor; // first local index that has to remain in buffer
int line;
/+invariant(){ // useless because DMD does not test the invariant at the proper time...
assert(e-s == (m-n+buffer.length)%buffer.length); // relation between (s,e) and (n,m)
assert(!(buffer.length&buffer.length-1)); // buffer size is always a power of two
assert(numAnchors||firstAnchor==size_t.max);
}+/
//pure: phobos ...
this(Source src){
source = src;
code = src.code.ptr[0..src.code.length+4]; // rely on 4 padding zero bytes
enum initsize=4096;//685438;//
buffer = new Token[](initsize);//
//buffer = (cast(Token*)malloc(Token.sizeof*initsize))[0..initsize];//
numAnchors=0;
firstAnchor=size_t.max;
line=1;
n=s=0;
e=lexTo(buffer);
m=e&buffer.length-1;
if(src.code.length > int.max) errors~=tokError("no support for sources exceeding 2GB",null),code.length=int.max;
}
@property ref const(Token) front()const{return buffer[n];}
@property bool empty(){return buffer[n].type==Tok!"EOF";}
void popFront(){
assert(!empty,"attempted to popFront empty lexer.");
n = n+1 & buffer.length-1; s++;
if(s<e) return; // if the buffer still contains elements
assert(s==e && n==m);
if(!numAnchors){// no anchors, that is easy, just reuse the whole buffer
buffer[0]=buffer[n-1&buffer.length-1]; // we want at least one token of lookback, for nice error reporting
e+=m=lexTo(buffer[n=1..$]);
m=m+1&buffer.length-1;
return;
}
assert(firstAnchor<buffer.length);
size_t num;
if(m < firstAnchor){ // there is an anchor but still space
num=lexTo(buffer[n..firstAnchor]);
e+=num; m=m+num&buffer.length-1;
return;
}else if(m > firstAnchor){ // ditto
num=lexTo(buffer[m..$]);
if(firstAnchor) num+=lexTo(buffer[0..firstAnchor]);
e+=num; m=m+num&buffer.length-1;
return;
}
auto len=buffer.length;
buffer.length=len<<1; // double buffer size
//buffer=(cast(Token*)realloc(buffer.ptr,(len<<1)*Token.sizeof))[0..len<<1];
n=len+firstAnchor; // move start and firstAnchor
buffer[len..n]=buffer[0..firstAnchor]; // move tokens to respect the new buffer topology
num=0;
if(n<buffer.length){
num=lexTo(buffer[n..$]);
e+=num; m=n+num&buffer.length-1;
}
if(!m&&firstAnchor){
num=lexTo(buffer[0..firstAnchor]);
e+=num; m=num&buffer.length-1;
}
}
Anchor pushAnchor(){
if(!numAnchors) firstAnchor=n;
numAnchors++;
return Anchor(s);
}
void popAnchor(Anchor anchor){
numAnchors--;
if(!numAnchors) firstAnchor=size_t.max;
n=n+anchor.index-s&buffer.length-1;
s=anchor.index;
}
private:
Token tokError(string s, string rep, int l=0){
auto r = token!"Error";
r.str = s;
r.loc = Location(rep, l?l:line);
return r;
}
size_t lexTo(Token[] res)in{assert(res.length);}body{
alias mallocAppender appender;
if(!code.length) return 0;
auto p=code.ptr;
auto s=p; // used if the input has to be sliced
auto sl=line;// ditto
char del; // used if a delimiter of some sort needs to be remembered
size_t len; // used as a temporary that stores the length of the last UTF sequence
size_t num=0;// number of tokens lexed, return value
typeof(p) invCharSeq_l=null;
void invCharSeq(){
if(p>invCharSeq_l+1) errors~=tokError("unsupported character",p[0..1]);
else errors[$-1].loc.rep=errors[$-1].loc.rep.ptr[0..errors[$-1].loc.rep.length+1];
invCharSeq_l=p; p++;
}
// text macros:
enum skipUnicode = q{if(*p<0x80){p++;break;} len=0; try utf.decode(p[0..4],len), p+=len; catch(Exception){invCharSeq();}};
enum skipUnicodeCont = q{if(*p<0x80){p++;continue;} len=0; try utf.decode(p[0..4],len), p+=len; catch(Exception){invCharSeq();}}; // don't break, continue
enum caseNl = q{case '\r': if(p[1]=='\n') p++; goto case; case '\n': line++; p++; continue;};
loop: while(res.length) { // breaks on EOF or buffer full
auto begin=p; // start of a token's representation
auto sline=line;
switch(*p++){
// whitespace
case 0, 0x1A:
res[0].type = Tok!"EOF";
res[0].loc.rep=p[0..1];
res[0].loc.line = line; // TODO: Why is this necessary?
res=res[1..$];
num++;
break loop;
case ' ', '\t', '\v':
continue; // ignore whitespace
case '\r': if(*p=='\n') p++; goto case;
case '\n': line++;
continue;
// ! can be the start of !is or !in tokens
enum lexNotAndNotIsAndNotIn=q{
s = p; int cline = line; // save p and line in case we will NOT find in or is
findnotinnotis: for(;;){
switch(*p){
case 'i': p++;
if(*p == 's') res[0].type = Tok!"!is";
else if(*p == 'n') res[0].type = Tok!"!in";
else goto default;
p++;
// make sure the identifier stops here:
if('a' <= *p && *p <='z') goto default;
if('A' <= *p && *p <='Z') goto default;
if('0' <= *p && *p <='9') goto default;
if(*p&0x80){
try{
auto ch=utf.decode(p[0..4],len);
if(isAlpha(ch)) goto default;
}catch(Exception){} goto default;
}
break findnotinnotis;
case ' ', '\t', '\v':
p++; continue; // ignore whitespace
case '\r': if(*++p=='\n') p++; goto case;
case '\n': line++;
p++; continue;
case 0x80: .. case 0xFF:
len=0;
try{
auto ch=utf.decode(p[0..4],len);
if(isWhite(ch)) p+=len; continue;
}catch(Exception){} goto default;
default:
res[0].type = Tok!"!";
p = s;
line = cline;
break findnotinnotis;
}
}
};
// simple tokens
mixin(caseSimpleToken());
// slash is special
case '/':
switch(*p){
case '=': res[0].type = Tok!"/="; p++;
break;
case '/': p++;
while(((*p!='\n') & (*p!='\r')) & ((*p!=0) & (*p!=0x1A))) mixin(skipUnicodeCont);
continue; // ignore comment
case '*':
s=p++-1;
sl=line;
consumecom2: for(;;){
switch(*p){
mixin(caseNl); // handle newlines
case '*': p++; if(*p=='/'){p++; break consumecom2;} break;
case 0, 0x1A: errors~=tokError("unterminated /* */ comment",s[0..p-s],sl); break consumecom2;
default: mixin(skipUnicode);
}
}
continue; // ignore comment
case '+':
int d=1;
s=p++-1;
sl=line;
consumecom3: while(d){
switch(*p){
mixin(caseNl); // handle newlines
case '+': p++; if(*p=='/') d--, p++; break;
case '/': p++; if(*p=='+') d++, p++; break;
case 0, 0x1A: errors~=tokError("unterminated /+ +/ comment",s[0..p-s],sl); break consumecom3;
default: mixin(skipUnicode);
}
}
continue; // ignore comment
default: res[0].type = Tok!"/"; break;
}
break;
// dot is special
case '.':
if('0' > *p || *p > '9'){
if(*p != '.') res[0].type = Tok!".";
else if(*++p!='.') res[0].type = Tok!"..";
else res[0].type = Tok!"...", p++;
break;
}
goto case;
// numeric literals
case '0': .. case '9':
res[0] = lexNumber(--p);
if(res[0].type == Tok!"Error") errors~=res[0], res[0].type=Tok!"__error";
break;
// character literals
case '\'':
s = p; sl = line;
res[0].type = Tok!"' '";
if(*p=='\\'){
try p++, res[0].int64 = cast(ulong)readEscapeSeq(p);
catch(EscapeSeqException e) if(e.msg) errors~=tokError(e.msg,e.loc); else invCharSeq();
}else{
try{
len=0;
res[0].int64 = utf.decode(p[0..4],len);
p+=len;
}catch(Exception){invCharSeq();}
}
if(*p!='\''){
//while((*p!='\''||(p++,0)) && *p && *p!=0x1A) mixin(skipUnicodeCont);
errors~=tokError("unterminated character constant",(s-1)[0..p-s+1],sl);
}else p++;
break;
// string literals
// WYSIWYG string/AWYSIWYG string
case 'r':
if(*p!='"') goto case 'R';
p++; del='"';
goto skipdel;
case '`':
del = '`'; skipdel:
s = p; sl = line;
readwysiwyg: for(;;){
if(*p==del){p++; break;}
switch(*p){
mixin(caseNl); // handle newlines
case 0, 0x1A:
errors~=tokError("unterminated string literal", (s-1)[0..1],sl);
break readwysiwyg;
default: mixin(skipUnicode);
}
}
res[0].type = Tok!"``";
res[0].str = s[0..p-s-1]; // reference to code
goto lexstringsuffix;
// token string
case 'q':
if(*p=='"') goto delimitedstring;
if(*p!='{') goto case 'Q';
p++; s = p; sl = line;
del = 0;
readtstring: for(int nest=1;;){ // TODO: implement more efficiently
Token tt;
code=code[p-code.ptr..$]; // update code to allow recursion
lexTo((&tt)[0..1]);
p=code.ptr;
switch(tt.type){
case Tok!"EOF":
errors~=tokError("unterminated token string literal", (s-2)[0..1], sl);
break readtstring;
case Tok!"{": nest++; break;
case Tok!"}": nest--; if(!nest) break readtstring; break;
default: break;
}
}
res[0].type = Tok!"``";
res[0].str = s[0..p-s-1]; // reference to code
goto lexstringsuffix;
delimitedstring:
res[0].type = Tok!"``";
s=++p; sl=line;
switch(*p){
case 'a': .. case 'z':
case 'A': .. case 'Z':
for(;;){
switch(*p){
case '\r': if(p[1]=='\n') p++; goto case;
case '\n': line++; break;
case 0, 0x1A: break;
case 'a': .. case 'z':
case 'A': .. case 'Z':
case '0': .. case '9':
p++;
continue;
case 0x80: .. case 0xFF:
len=0;
try{auto ch=utf.decode(p[0..4],len);
if(isAlpha(ch)){p+=len; continue;}
break;
}catch(Exception){invCharSeq(); break;}
default: break;
}
break;
}
if(*p!='\n' && *p!='\r') errors~=tokError("heredoc identifier must be followed by a new line",p[0..1]);
while(((*p!='\n') & (*p!='\r')) & ((*p!=0) & (*p!=0x1A))) mixin(skipUnicodeCont); // mere error handling
auto ident=s[0..p-s];
if(*p=='\r'){line++;p++;if(*p=='\n') p++;}
else if(*p=='\n'){line++;p++;}
s=p;
readheredoc: while((*p!=0) & (*p!=0x1A)){ // always at start of new line here
for(auto ip=ident.ptr, end=ident.ptr+ident.length;;){
if(ip==end) break readheredoc;
switch(*p){
mixin(caseNl);
case 0x80: .. case 0xFF:
len=0;
try{auto ch=utf.decode(p[0..4],len);
if(isAlpha(ch)){
if(p[0..len]!=ip[0..len]) break;
p+=len; ip+=len; continue;
}
break;
}catch(Exception){invCharSeq(); break;}
default:
if(*p!=*ip) break;
p++; ip++; continue;
}
break;
}
while(((*p!='\n') & (*p!='\r')) & ((*p!=0) & (*p!=0x1A))) mixin(skipUnicodeCont);
if(*p=='\r'){line++;p++;if(*p=='\n') p++;}
else if(*p=='\n'){line++;p++;}
}
res[0].str = p>s+ident.length?s[0..p-s-ident.length]:""; // reference to code
if(*p!='"') errors~=tokError("unterminated heredoc string literal",(s-1)[0..1],sl);
else p++;
break;
default:
del=*p; char rdel=del; dchar ddel=0;
switch(del){
case '[': rdel=']'; s=++p; break;
case '(': rdel=')'; s=++p; break;
case '<': rdel='>'; s=++p; break;
case '{': rdel='}'; s=++p; break;
case '\r': if(p[1]=='\n') p++; goto case;
case '\n': line++; p++; goto case;
case ' ','\t','\v':
errors~=tokError("string delimiter cannot be whitespace",p[0..1]);
goto case;
case 0x80: case 0xFF:
s=p;
len=0;
try{
ddel=utf.decode(p[0..4],len);
s=p+=len;
}catch(Exception){invCharSeq();}
break;
default: p++; break;
}
if(ddel){
while((*p!=0) & (*p!=0x1A)){
if(*p=='\r'){line++;p++;if(*p=='\n') p++;}
else if(*p=='\n'){line++;p++;}
else if(*p<0x80){p++; continue;}
try{
auto x=utf.decode(p[0..4],len);
if(ddel==x){
res[0].str = s[0..p-s]; // reference to code
p+=len; break;
}
p+=len;
}catch(Exception){invCharSeq();}
}
}else{
for(int nest=1;(nest!=0) & (*p!=0) & (*p!=0x1A);){
if(*p=='\r'){line++;p++;if(*p=='\n') p++;}
else if(*p=='\n'){line++;p++;}
else if(*p==rdel){nest--; p++;}
else if(*p==del){nest++; p++;}
else if(*p & 0x80){
try{
utf.decode(p[0..4],len);
p+=len;
}catch(Exception){invCharSeq();}
}else p++;
}
res[0].str = s[0..p-s-1]; // reference to code
}
if(*p!='"'){
if(*p) errors~=tokError("expected '\"' to close delimited string literal",p[0..1]);
else errors~=tokError("unterminated delimited string literal",(s-2)[0..1],sl);
}else p++;
break;
}
goto lexstringsuffix;
// Hex string
case 'x':
if(*p!='"') goto case 'X';
auto r=appender!string(); p++; s=p; sl=line;
readhexstring: for(int c=0,ch,d;;p++,c++){
switch(*p){
mixin(caseNl); // handle newlines
case ' ', '\t', '\v': c--; break;
case 0, 0x1A:
errors~=tokError("unterminated hex string literal",(s-1)[0..1],sl);
break readhexstring;
case '0': .. case '9': d=*p-'0'; goto handlexchar;
case 'a': .. case 'f': d=*p-('a'-0xa); goto handlexchar;
case 'A': .. case 'F': d=*p-('A'-0xA); goto handlexchar;
handlexchar:
if(c&1) r.put(cast(char)(ch|d));
else ch=d<<4; break;
case '"':
if(c&1) errors~=tokError(format("found %s character%s when expecting an even number of hex digits",toEngNum(c),c!=1?"s":""),s[0..p-s]);
p++; break readhexstring;
default:
if(*p<128) errors~=tokError(format("found '%s' when expecting hex digit",*p),p[0..1]);
else{
s=p;
len=0;
try{
auto chr = utf.decode(p[0..4],len);
p+=len-1;
if(isWhite(chr)) break; //TODO: newlines
}catch(Exception){invCharSeq();}
errors~=tokError(format("found '%s' when expecting hex digit",s[0..len]),s[0..len]);
}
break;
}
}
res[0].type = Tok!"``";
res[0].str = r.data;
goto lexstringsuffix;
// DQString
case '"':
{
// appender only used if there is an escape sequence, slice otherwise
// TODO: how costly is eager initialization?
auto r=appender!string();
auto start = s = p;
readdqstring: for(;;){
switch(*p){
mixin(caseNl);
case 0, 0x1A:
errors~=tokError("unterminated string literal",(start-1)[0..1]);
break readdqstring;
case '\\':
r.put(s[0..p++-s]);
try r.put(readEscapeSeq(p));
catch(EscapeSeqException e) if(e.msg) errors~=tokError(e.msg,e.loc); else invCharSeq();
s = p;
continue;
case '"': p++; break readdqstring;
default: mixin(skipUnicode);
}
}
res[0].type = Tok!"``";
if(!r.data.length) res[0].str = start[0..p-1-start];
else{ r.put(s[0..p-1-s]); res[0].str = r.data; }
goto lexstringsuffix;
}
lexstringsuffix:
if(*p=='c') res[0].type = Tok!"``c", p++;
else if(*p=='w') res[0].type = Tok!"``w", p++;
else if(*p=='d') res[0].type = Tok!"``d", p++;
break;
// identifiers and keywords
case '_':
case 'a': .. case 'p': /*q, r*/ case 's': .. case 'w': /*x*/ case 'y', 'z':
case 'A': .. case 'Z':
s = p-1;
identifier:
readident: for(;;){
switch(*p){
case '_':
case 'a': .. case 'z':
case 'A': .. case 'Z':
case '0': .. case '9':
p++;
break;
case 0x80: .. case 0xFF:
len=0;
try if(isAlpha(utf.decode(p[0..4],len))) p+=len;
else break readident;
catch(Exception){break readident;} // will be caught in the next iteration
break;
default: break readident;
}
}
res[0].name = s[0..p-s];
res[0].type=isKeyword(res[0].name);
break;
case 0x80: .. case 0xFF:
len=0; p--;
try{auto ch=utf.decode(p[0..4],len);
s=p, p+=len;
if(isAlpha(ch)) goto identifier;
if(!isWhite(ch)) errors~=tokError(format("unsupported character '%s'",ch),s[0..len]);
// else if(isNewLine(ch)) line++; // TODO: implement this everywhere
continue;
}catch(Exception){} goto default;
default:
p--; invCharSeq(); p++;
continue;
}
res[0].loc.rep=begin[0..p-begin];
res[0].loc.line=sline;
res=res[1..$];
num++;
}
code=code[p-code.ptr..$];
return num;
}
/* Lex a number FSM. TDPL p33/35
Returns either a valid literal token or one of the following:
errExp = tokError("exponent expected");
errsOverflow = tokError("signed integer constant exceeds long.max");
errOverflow = tokError("integer constant exceeds ulong.max");
//errRepr = tokError("numerical constant is not representable in [float|double|real]");
errOctDepr = tokError("octal literals are deprecated");
*/
private Token lexNumber(ref immutable(char)* _p){
static assert(real.mant_dig <= 64);
auto p = _p;
enum dlim = ulong.max / 10; // limit for decimal values (prevents overflow)
enum helim = int.max / 10; // ditto for binary exponent (hex floats)
enum elim = int.max / 10; // ditto for exponent
Token tok;
bool leadingzero = 0;
bool isfloat = 0;// true if floating point literal
bool isimag = 0; // true if imaginary floating point literal. as in DMD, this only works for decimals
bool toobig = 0;// true if value exceeds ulong.max
ulong val = 0; // current literal value
real rval = 0.0L;// real value
long exp = 0; // exponent
bool neg = 0; // exponent is negative
int dig = 0; // number of consumed digits
int dot = -1; // position of decimal dot, counted from the left (-1=not encountered yet)
int adjexp = 0; // exponent adjustment due to very long literal
enum : int {DEC, BIN, OCT, HEX}
int base = DEC;
// powers of 2 and 10 for fast computation of rval given the mantissa and exponents. (TODO: Get rid of pw2)
static immutable pw2 = mixin("["~{string r; foreach(i;0..16) r~="0x1p"~to!string(1L<<i)~"L,"; return r;}()~"]");
static immutable pw10= mixin("["~{string r; for(int i=15;i>=0;i--) r~= "1e"~to!string(1L<<i)~"L,"; return r;}()~"]");
static immutable pn10= mixin("["~{string r; for(int i=15;i>=0;i--) r~= "1e-"~to!string(1L<<i)~"L,"; return r;}()~"]");
selectbase: switch(*p){
case '0':
p++;
switch(*p){
case 'x', 'X':
p++;
base = HEX;
while(*p == '0') p++; // eat leading zeros
readhex: for(;dig<16;p++){
switch(*p){
case '0': .. case '9':
val = val << 4 | *p-'0'; dig++;
break;
case 'a': .. case 'f':
val = val << 4 | *p-('a'-0xa); dig++;
break;
case 'A': .. case 'F':
val = val << 4 | *p-('A'-0xA); dig++;
break;
case '.':
if(p[1] != '.' && dot == -1) dot = dig, isfloat=1;
else break readhex; goto case;
case '_': // ignore embedded _
break;
default:
break readhex;
}
}
if(dig == 16 && ('8' <= *p && *p <= '9' || 'a' <= *p && *p <= 'f' || 'A' <=*p && *p <= 'F')){ // round properly
val++;
if(!val) val = 1, adjexp = 16; // cope with overflow
}
consumehex: for(;;p++){
switch(*p){
case '0': .. case '9':
case 'a': .. case 'f':
case 'A': .. case 'F':
dig++; adjexp++;
break;
case '.':
if(p[1] != '.' && dot == -1) dot = dig, isfloat = 1; // break; }
else break consumehex; goto case;
case '_': // ignore embedded _
break;
case 'p', 'P':
isfloat = 1;
p++;
neg = 0;
switch(*p){
case '-': neg = 1; goto case;
case '+': p++; goto default;
default: break;
}
if('0'> *p || *p > '9') goto Lexp;
readhexp: for(;;p++){
switch(*p){
case '0': .. case '9':
exp = (exp << 1) + (exp << 3) + *p -'0';
break;
case '_': // ignore embedded _.
break;
default:
break readhexp;
}
if(exp > helim){p++;break readhexp;}
}
goto default;
default:
break consumehex;
}
}
isfloat |= *p == 'f' || *p == 'F';
if(isfloat){ // compute value of hex floating point literal
if(dot==-1) dot = dig;
if(neg) exp += dig - dot - adjexp << 2L;
else exp -= dig - dot - adjexp << 2L;
if(exp<0) neg = !neg, exp=-exp;
if('0' <= *p && *p <= '9' || exp>=8184 || !val){
p++, rval = neg || !val ? .0L : real.infinity;
while('0' <= *p && *p <= '9') p++;
}else{ // TODO: Could construct value directly in memory
rval = 1.0L;
for(int i=0,j=cast(int)(exp&-1u);i<16;i++,j>>=1) if(j&1) rval*=pw2[i];
if(neg) rval = val / rval;
else rval *= val;
}
}
if(adjexp) val = ulong.max; // for error handling
break selectbase;
case 'b', 'B':
p++;
base = BIN;
readbin: for(;dig<64;p++){
switch(*p){
case '0', '1':
val <<= 1; dig++;
val |= *p-'0'; goto case;
case '_': // ignore embedded _
break;
default:
break readbin;
}
}
break selectbase;
/*case 'o': // non-standard
base = OCT;*/
default: // 0xxx-style octal is deprecated, interpret as decimal and give an error
leadingzero = 1;
break;
}
while(*p == '0') p++; // eat leading zeros of decimal
if(('1' > *p || *p > '9') && *p != '.'){
isfloat |= *p == 'f' || *p == 'F' || *p == 'i' || *p == 'L' && p[1]=='i';
leadingzero=0; break;
}
goto case;
case '1': .. case '9': case '.':
readdec: for(;;p++){
switch(*p){
case '0': .. case '9':
val = (val << 1) + (val << 3) + *p -'0'; dig++;
break;
case '.':
if('0'<=p[1]&&p[1]<='9' && dot == -1) dot = dig, isfloat=1; // break; }
else break readdec; goto case;
case '_': // ignore embedded _
break;
default:
break readdec;
}
if(val >= dlim){
p++;
if(val > dlim) break readdec;
if('0' <= *p && *p <= '5') val = (val << 1) + (val << 3) + *p -'0', dig++, p++;
break readdec;