module nimpc.lexer;

import streams;
import std.stdio;
import std.regex;
import std.array;

enum TokenType {
    KEYWORD,
    DATA_TYPE,
    SENTENCE_END,
    LITERAL_INTEGER,
    LITERAL_FLOAT,
    LITERAL_BOOLEAN,
    LITERAL_STRING
}

struct Token {
    TokenType type;
    string content;
    uint line;
    uint column;
}

class LexerException : Exception {
    const uint sourceLine;
    const uint sourceColumn;

    this(string msg, uint sourceLine, uint sourceColumn) {
        super(msg);
        this.sourceLine = sourceLine;
        this.sourceColumn = sourceColumn;
    }
}

/**
 * Parses a list of tokens from an input stream of lines of code.
 * Params:
 *   inputStream = The lines of input to parse.
 * Returns: A list of tokens.
 */
Token[] tokenize(S)(S inputStream) if (isInputStream!(S, char)) {
    Appender!(Token[]) tokenApp;
    uint line = 0;
    uint col = 0;

    while (true) {
        char c = readChar(inputStream, line, col);
        writeln(c);
    }


    return tokenApp[];
}

private char readChar(S)(S stream, uint line, uint col) if (isInputStream!(S, char)) {
    auto result = readOne(stream);
    if (result.hasError) {
        throw new LexerException("Failed to read one more char from stream.", line, col);
    }
    return result.element;
}