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revamped lexer code to be more flexible

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This commit is contained in:
Valerie Wolfe 2024-04-02 23:33:50 -04:00
parent ff05782056
commit e4ad03774e
1 changed files with 52 additions and 44 deletions
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96
src/Lex.cs
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@ -2,51 +2,65 @@ using System.Text.RegularExpressions;
using Dungeoneer.Error;
namespace Dungeoneer.Lexing {
namespace Dungeoneer.Interpreter {
public static class Lexer {
public static readonly char[] Delimiters = { ' ', '+', '-', '*', '/', '^' };
public static readonly char[] Operators = { '+', '-', '*', '/', '^' };
public static TokenSet Tokenize(string text) {
var output = new TokenSet();
var parts = text.Trim().Split(" ", 0x11);
foreach(string part in parts) {
var diceMatch = DiceToken.Match(part);
if(diceMatch.Success) {
output.Add(new DiceToken(diceMatch));
continue;
}
var numberMatch = NumberToken.Match(part);
if(numberMatch.Success) {
output.Add(new NumberToken(numberMatch));
continue;
}
var dcMatch = DcToken.Match(part);
if(dcMatch.Success) {
output.Add(new DcToken(dcMatch));
continue;
}
var operatorMatch = OperatorToken.Match(part);
if(operatorMatch.Success) {
output.Add(new OperatorToken(operatorMatch));
continue;
}
var varMatch = VarToken.Match(part);
if(varMatch.Success) {
output.Add(new VarToken(varMatch));
continue;
}
throw new UnmatchedTokenException(part);
/* - iterate over input characters:
* - create a buffer of text characters
* - if a delimiter is found:
* - consume the buffer into a token and add to output
* - if the delimiter was an operator, add its token to output
* - when the string terminates, consume the buffer
*/
string buffer = "";
foreach(char c in text) {
if(Delimiters.Contains(c)) {
if(buffer.Length != 0) {
Console.WriteLine(buffer);
var token = Match(buffer);
output.Add(token);
}
if(Operators.Contains(c))
output.Add(new OperatorToken(c));
buffer = "";
} else
buffer += c;
}
if(buffer.Length != 0)
output.Add(Match(buffer));
return output;
}
public static Token Match(string text) {
var diceMatch = DiceToken.Match(text);
if(diceMatch.Success)
return new DiceToken(diceMatch);
var numberMatch = NumberToken.Match(text);
if(numberMatch.Success)
return new NumberToken(numberMatch);
var dcMatch = DcToken.Match(text);
if(dcMatch.Success)
return new DcToken(dcMatch);
var varMatch = VarToken.Match(text);
if(varMatch.Success)
return new VarToken(varMatch);
throw new UnmatchedTokenException(text);
}
}
public class TokenSet : List<Token> {
@ -57,7 +71,7 @@ namespace Dungeoneer.Lexing {
var output = "";
foreach(Token token in this)
output += $"{token} ";
return output;
return output.Trim();
}
}
@ -79,17 +93,11 @@ namespace Dungeoneer.Lexing {
}
public class OperatorToken : Token {
public string dummy;
public char Value;
internal static readonly Regex Pattern = new Regex(@"([\+\-\*\/])");
public OperatorToken(char op) { Value = op; }
public OperatorToken(Match match) {
dummy = match.Groups[1].Value;
}
public override string ToString() { return dummy; }
public static Match Match(string text) { return Pattern.Match(text); }
public override string ToString() { return Value.ToString(); }
}