class-compiler/process-comments.cc at main · toliy-dev/class-compiler · GitHub

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#include "buffered-input.h"
#include "lex.h"

/*
* If a # is encountered, begin processing line as line comment
*
* Comments are not Tokens, and
* all characters in a comment will be skipped
*
* @return Error NCC_OK if no errors occur
*               NCC_UNEXPECTED_EOF if EOF is reached before \n
*/
Error process_line_comment()
{
    char c;
    // advance buffer location until EOF or \n is encountered
    while (buffer_get_next_char(c) != -1 && c != '\n');

    // if EOF is reached before \n, it is an error
    if (lex_eof())
        return Error { NCC_UNEXPECTED_EOF, src_line_no, src_col_no };

    return Error { NCC_OK, src_line_no, src_col_no };
}

/*
* If a <<- is encountered, begin processing following chars as a block comment
* until ->> is encountered
*
* Comments are not Tokens, and
* all characters in a comment will be skipped
*
* @return Error NCC_OK if no errors occur
*               NCC_UNEXPECTED_EOF if EOF is reached before ->>
*/
Error process_block_comment()
{
    char c;
    // assume <<- is true
    bool block_start_token = true;

    // retrieve next character
    buffer_get_next_char(c);

    // if not <<, then this is not block comment
    if (c != '<')
    {
        // <<- is not true
        block_start_token = false;
        // shift back 2 characters to process < as Token
        buffer_back_char();
        buffer_back_char();
        return Error { NCC_OK, src_line_no, src_col_no };
    }

    // retrieve next character
    buffer_get_next_char(c);

    // if not <<-, then this is not block comment
    if (block_start_token && c != '-')
    {
        // <<- is not true
        block_start_token = false;
        // shift back 3 characters to process < as Token
        buffer_back_char();
        buffer_back_char();
        buffer_back_char();
        return Error { NCC_OK, src_line_no, src_col_no };
    }

    // retrieve characters until EOF
    while (buffer_get_next_char(c) != -1)
    {
        // - part of ->> is found
        if (c == '-')
        {
            // if not ->, this is not the end of a block comment
            buffer_get_next_char(c);
            if (c != '>')
                continue; // start loop from beginning

            // if not ->>, this is not the end of a block comment
            buffer_get_next_char(c);
            if (c == '>')
                break;    // exit out of loop
        }
    }

    // EOF encountered before ->>
    if (lex_eof())
        return Error { NCC_UNEXPECTED_EOF, src_line_no, src_col_no };

    return Error { NCC_OK, src_line_no, src_col_no };
}