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Tokenizer.cs
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Tokenizer.cs
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// File encoding should remain in UTF-8!
using System;
using System.IO;
using System.Collections.Generic;
namespace Kerbulator {
public enum TokenType {
EMPTY,
NUMBER,
IDENTIFIER,
OPERATOR,
BRACE,
LIST,
END,
ASSIGN,
COMMA,
COLON,
TEXT,
IN,
OUT,
MANEUVER,
ALARM,
SKIP_NEWLINE,
PIECEWISE,
CONDITIONAL
};
public class Token {
public TokenType type;
public string val;
public string func;
public int line;
public int col;
public Token() {
this.type = TokenType.EMPTY;
this.val = "";
this.func = null;
this.line = -1;
this.col = -1;
}
public Token(string func, int line, int col) {
this.type = TokenType.EMPTY;
this.val = "";
this.func = func;
this.line = line;
this.col = col;
}
public Token(TokenType type, string val) {
this.type = type;
this.val = val;
this.func = null;
this.line = -1;
this.col = -1;
}
public Token(TokenType type, string val, string func, int line, int col) {
this.type = type;
this.val = val;
this.func = func;
this.line = line;
this.col = col;
}
override public string ToString() {
return Enum.GetName(typeof(TokenType), this.type) +": "+ this.val;
}
public string pos {
get {
string err = "";
if(func != null)
err += "In function "+ func;
if(line > 0) {
err += " (line "+ line;
if(col > 0)
err += ", col "+ col;
err += ")";
}
return err +": ";
}
protected set {}
}
}
public class Tokenizer {
public Queue<Token> tokens;
private string functionName;
public Tokenizer(string functionName) {
tokens = new Queue<Token>();
this.functionName = functionName;
}
public void Tokenize(string line) {
int lineno = 1;
int col = 1;
Token tok = new Token(functionName, lineno, col);
for(int i=0; i<line.Length; i++, col++) {
char c = line[i];
switch(c)
{
// Whitespace
case ' ':
case '\t':
case '\r':
if(tok.type != TokenType.SKIP_NEWLINE) {
HandleToken(tok);
tok = new Token(functionName, lineno, col + 1);
}
break;
// End of statement
case '\n':
if(tok.type != TokenType.SKIP_NEWLINE) {
HandleToken(tok);
HandleToken(new Token(TokenType.END, "\\n", functionName, lineno, col));
}
lineno ++;
col = 0;
tok = new Token(functionName, lineno, col + 1);
break;
// Comments
case '#':
HandleToken(tok);
// Skip to next newline
int newI = line.IndexOf('\n', i+1) - 1;
if(newI < 0)
newI = line.Length-1;
col += newI - i;
i = newI;
tok = new Token(functionName, lineno, col);
break;
// Quoted strings
case '"':
HandleToken(tok);
tok = new Token(TokenType.TEXT, "", functionName, lineno, col);
// Read until next unescaped "
bool terminated = false;
for(i=i+1, col++; i<line.Length; i++, col++) {
if(line[i] == '\\') {
if(i >= line.Length - 1)
break;
tok.val += line[i+1];
i += 2; col += 2;
} else if(line[i] == '"') {
terminated = true;
break;
} else {
tok.val += line[i];
}
}
if(!terminated)
throw new Exception(tok.pos + "missing end quote (\") for string");
HandleToken(tok);
tok = new Token(functionName, lineno, col);
break;
// Numbers
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
if(tok.type == TokenType.EMPTY) {
tok.type = TokenType.NUMBER;
tok.val = c.ToString();
} else if(tok.type == TokenType.NUMBER || tok.type == TokenType.IDENTIFIER)
tok.val += c;
else
throw new Exception(tok.pos + c +" is invalid here");
break;
case 'e':
case 'E':
if(tok.type == TokenType.EMPTY) {
tok.type = TokenType.IDENTIFIER;
tok.val = c.ToString();
} else if(tok.type == TokenType.NUMBER || tok.type == TokenType.IDENTIFIER) {
tok.val += c;
if(i < line.Length - 1 && line[i+1] == '-') {
tok.val += line[i+1].ToString();
i++; col++;
}
} else
throw new Exception(tok.pos + c +" is invalid here");
break;
case '.':
if(tok.type == TokenType.EMPTY) {
tok.type = TokenType.NUMBER;
tok.val = c.ToString();
} else if(tok.type == TokenType.NUMBER) {
if(tok.val.IndexOf(c) >= 0)
throw new Exception(tok.pos +"numbers can only have one decimal point (.) in them");
tok.val += c;
} else if(tok.type == TokenType.IDENTIFIER) {
tok.val += c;
} else
throw new Exception(tok.pos +"variable/function names cannot start with a dot (.)");
break;
// Operators
case '-':
case '+':
case '/':
case '÷':
case '√':
case '%':
case '*':
case '·':
case '×':
case '^':
case '≤':
case '≥':
case '≠':
case '¬':
case '∧':
case '∨':
HandleToken(tok);
HandleToken(new Token(TokenType.OPERATOR, c.ToString(), functionName, lineno, col));
tok = new Token(functionName, lineno, col + 1);
break;
// Operators that can possibly expand to two characters (<=, =>, ==, !=)
case '<':
HandleToken(tok);
if(i < line.Length - 1 && line[i+1] == '=') {
HandleToken(new Token(TokenType.OPERATOR, "<=", functionName, lineno, col));
col++; i++;
} else {
HandleToken(new Token(TokenType.OPERATOR, "<", functionName, lineno, col));
}
tok = new Token(functionName, lineno, col + 1);
break;
case '>':
HandleToken(tok);
if(i < line.Length - 1 && line[i+1] == '=') {
HandleToken(new Token(TokenType.OPERATOR, ">=", functionName, lineno, col));
col++; i++;
} else {
HandleToken(new Token(TokenType.OPERATOR, ">", functionName, lineno, col));
}
tok = new Token(functionName, lineno, col + 1);
break;
case '!':
HandleToken(tok);
if(i < line.Length - 1 && line[i+1] == '=') {
HandleToken(new Token(TokenType.OPERATOR, "!=", functionName, lineno, col));
col++; i++;
} else {
HandleToken(new Token(TokenType.OPERATOR, "!", functionName, lineno, col));
}
tok = new Token(functionName, lineno, col + 1);
break;
// The =, ==, ={ case
case '=':
HandleToken(tok);
if(i < line.Length - 1 && line[i+1] == '=') {
HandleToken(new Token(TokenType.OPERATOR, "==", functionName, lineno, col));
col++; i++;
} else if(i < line.Length - 1 && line[i+1] == '{') {
HandleToken(new Token(TokenType.PIECEWISE, "={", functionName, lineno, col));
col++; i++;
} else {
HandleToken(new Token(TokenType.ASSIGN, "=", functionName, lineno, col));
}
tok = new Token(functionName, lineno, col + 1);
break;
// Brackets
case '[':
case ']':
HandleToken(tok);
HandleToken(new Token(TokenType.LIST, c.ToString(), functionName, lineno, col));
tok = new Token(functionName, lineno, col + 1);
break;
case '(':
case ')':
case '{':
case '}':
case '⌊':
case '⌋':
case '⌈':
case '⌉':
case '|':
HandleToken(tok);
HandleToken(new Token(TokenType.BRACE, c.ToString(), functionName, lineno, col));
tok = new Token(functionName, lineno, col + 1);
break;
// In: and Out: statements
case ':':
if(tok.val == "in")
HandleToken(new Token(TokenType.IN, tok.val, functionName, lineno, col));
else if(tok.val == "out")
HandleToken(new Token(TokenType.OUT, tok.val, functionName, lineno, col));
else if(tok.val == "maneuver")
HandleToken(new Token(TokenType.MANEUVER, tok.val, functionName, lineno, col));
else if(tok.val == "alarm")
HandleToken(new Token(TokenType.ALARM, tok.val, functionName, lineno, col));
else {
HandleToken(tok);
HandleToken(new Token(TokenType.COLON, tok.val, functionName, lineno, col));
}
tok = new Token(functionName, lineno, col + 1);
break;
// Others
case ',':
HandleToken(tok);
HandleToken(new Token(TokenType.COMMA, c.ToString(), functionName, lineno, col));
tok = new Token(functionName, lineno, col + 1);
break;
case '\\':
HandleToken(tok);
tok = new Token(TokenType.SKIP_NEWLINE, c.ToString(), functionName, lineno, col);
break;
default:
if(tok.type != TokenType.EMPTY && tok.type != TokenType.IDENTIFIER)
throw new Exception(tok.pos + "unexpected character: "+ c);
tok.type = TokenType.IDENTIFIER;
tok.val += c;
break;
}
}
HandleToken(tok);
Kerbulator.Debug("\n");
}
private void HandleToken(Token t) {
switch(t.type) {
case TokenType.EMPTY:
return;
// Some identifiers are special
case TokenType.IDENTIFIER:
// These are actually operators
if(t.val == "and" || t.val == "or")
t.type = TokenType.OPERATOR;
// These are actually conditionals
else if(t.val == "if" || t.val == "otherwise")
t.type = TokenType.CONDITIONAL;
break;
}
Kerbulator.Debug(" "+ t.ToString());
tokens.Enqueue(t);
}
}
}