Nasal-Interpreter/test/lexer.nas

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use std.io;
var lexer = func(file) {
var (ptr,token)=(0,[]);
var s=io.readfile(file);
var len=size(s);
var line=0;
var gen = func(tok) {
append(token,{
line:line,
token:tok
});
}
return {
jmp_note:func() {
while (ptr<len and s[ptr]!='\n'[0])
ptr+=1;
if (ptr<len and s[ptr]=='\n'[0])
line+=1;
ptr+=1;
},
id_gen:func() {
var tmp="";
while (ptr<len) {
var c=s[ptr];
if (('a'[0]<=c and c<='z'[0])
or ('A'[0]<=c and c<='Z'[0])
or ('0'[0]<=c and c<='9'[0])
or c=='_'[0])
tmp~=chr(c);
else
break;
ptr+=1;
}
gen(tmp);
},
str_gen:func() {
var str="";
var mark=chr(s[ptr]);
ptr+=1;
while (ptr<len and chr(s[ptr])!=mark) {
if (chr(s[ptr])=='\\') {
ptr+=1;
var c=chr(s[ptr]);
if (c=='a' ) str~='\a';
elsif (c=='b' ) str~='\b';
elsif (c=='e' ) str~='\e';
elsif (c=='f' ) str~='\f';
elsif (c=='n' ) str~='\n';
elsif (c=='r' ) str~='\r';
elsif (c=='t' ) str~='\t';
elsif (c=='v' ) str~='\v';
elsif (c=='?' ) str~='\?';
elsif (c=='0' ) str~='\0';
elsif (c=='\\') str~='\\';
elsif (c=='\'') str~='\'';
elsif (c=='\"') str~='\"';
else str~=c;
} else {
if (s[ptr]=='\n'[0])
line+=1;
str~=chr(s[ptr]);
}
ptr+=1;
}
if (ptr>=len)
print("read eof when generating string.\n");
ptr+=1;
gen(str);
},
num_gen:func() {
var number=chr(s[ptr]);
ptr+=1;
if (ptr<len and chr(s[ptr])=='x') {
ptr+=1;
while (ptr<len and
('a'[0]<=s[ptr] and s[ptr]<='f'[0]
or '0'[0]<=s[ptr] and s[ptr]<='9'[0])) {
number~=chr(s[ptr]);
ptr+=1;
}
gen(num(number));
return;
} elsif (ptr<len and chr(s[ptr])=='o') {
ptr+=1;
while (ptr<len and ('0'[0]<=s[ptr] and s[ptr]<='7'[0])) {
number~=chr(s[ptr]);
ptr+=1;
}
gen(num(number));
return;
}
while (ptr<len and ('0'[0]<=s[ptr] and s[ptr]<='9'[0])) {
number~=chr(s[ptr]);
ptr+=1;
}
if (ptr<len and chr(s[ptr])=='.') {
number~=chr(s[ptr]);
ptr+=1;
while (ptr<len and ('0'[0]<=s[ptr] and s[ptr]<='9'[0])) {
number~=chr(s[ptr]);
ptr+=1;
}
}
if (chr(s[ptr])=='e' or chr(s[ptr])=='E') {
number~=chr(s[ptr]);
ptr+=1;
if (chr(s[ptr])=='-' or chr(s[ptr])=='+') {
number~=chr(s[ptr]);
ptr+=1;
}
while (ptr<len and ('0'[0]<=s[ptr] and s[ptr]<='9'[0])) {
number~=chr(s[ptr]);
ptr+=1;
}
}
var last_c=chr(number[-1]);
if (last_c=='.' or last_c=='e' or last_c=='E' or last_c=='-' or last_c=='+')
println("error number: ",number);
gen(num(number));
},
opr_gen:func() {
var c=chr(s[ptr]);
if (c=='+' or c=='-' or c=='~' or c=='/' or c=='*' or c=='>' or c=='<' or c=='!' or c=='=') {
var tmp=c;
ptr+=1;
if (ptr<len and chr(s[ptr])=='=') {
tmp~=chr(s[ptr]);
ptr+=1;
}
gen(tmp);
return;
} elsif (c=='.') {
if (ptr+2<len and chr(s[ptr+1])=='.' and chr(s[ptr+2])=='.') {
gen("...");
ptr+=3;
}
else {
gen(".");
ptr+=1;
}
return;
}
elsif (c!=' ' and c!='\t' and c!='\n' and c!='\r' and s[ptr]>0)
gen(c);
ptr+=1;
return;
},
compile:func() {
line=1;
while (ptr<len) {
var c=s[ptr];
if (c=='#'[0])
me.jmp_note();
elsif (c=='\n'[0]) {
line+=1;
ptr+=1;
}
elsif ('a'[0]<=c and c<='z'[0]
or 'A'[0]<=c and c<='Z'[0]
or c=='_'[0])
me.id_gen();
elsif (c=='\''[0] or c=='\"'[0])
me.str_gen();
elsif ('0'[0]<=c and c<='9'[0])
me.num_gen();
else
me.opr_gen();
}
return;
},
get_token:func() {return token;}
};
}
var lex=lexer("std/fg_env.nas");
lex.compile();
foreach(var tok;lex.get_token())
print('(',tok.line,' | ',tok.token,')\n');