To render problem messages either as plain text or HTML, and write them out to files.

• §1. Buffering
• §7. Problems report and index

§1. Buffering. Only one error text needs to be stored in memory at any one time, so we keep it in a single text stream:

text_stream *PBUFF = NULL;

void ProblemBuffer::clear?Usage of ProblemBuffer::clear:
Problems, Level 2 - §3.1, §10(void) {
    if (PBUFF == NULL) PBUFF = Str::new();
    else Str::clear(PBUFF);
}

§2. Roughly speaking, text for problem messages comes from two possible sources: fairly short standard texts inside Inform, and quotations (direct or indirect) from the source text. The latter are inserted by the routines in this section, and they are the ones we should be wary of, since bizarre input might cause absurdly long quotations to be made. A quotation involves copying text from word w1 to w2, so there are two dangers: copying a single very long word, or copying too many of them. We protect against the first by using the %<W escape, which truncates long literals. We protect against the second overflow hazard by limiting the amount of text we are prepared to quote from any sentence in one go:

define QUOTATION_TOLERANCE_LIMIT 100

void ProblemBuffer::copy_text?Usage of ProblemBuffer::copy_text:
§4
Problems, Level 2 - §3.1, §13.1.2(wording W) {
    W = Wordings::truncate(W, QUOTATION_TOLERANCE_LIMIT);
    WRITE_TO(PBUFF, "%<W", W);
}

§3. Diverting source quotes.

parse_node *redirected_sentence = NULL;
parse_node *redirected_to_A = NULL, *redirected_to_B = NULL;
void ProblemBuffer::redirect_problem_sentence(parse_node *from,
    parse_node *A, parse_node *B) {
    redirected_sentence = from; redirected_to_A = A; redirected_to_B = B;
}

§4. These three special character codes are used as a temporary measure to mask out angle brackets and quotation marks which we don't want to interpret as HTML:

define PROTECTED_LT_CHAR L'\x01'
define PROTECTED_GT_CHAR L'\x02'
define PROTECTED_QUOT_CHAR L'\x03'

void ProblemBuffer::copy_source_reference?Usage of ProblemBuffer::copy_source_reference:
Problems, Level 2 - §12, §13.1.2(wording W) {
    if (Wordings::empty(W)) { WRITE_TO(PBUFF, "<no text>"); return; }
    source_file *referred = Lexer::file_of_origin(Wordings::first_wn(W));
    TEMPORARY_TEXT(file)
    if (referred) {
        WRITE_TO(file, "%f", TextFromFiles::get_filename(referred));
        pathname *proj = HTML::get_link_abbreviation_path();
        if (proj) {
            TEMPORARY_TEXT(project_prefix)
            WRITE_TO(project_prefix, "%p", proj);
            if (Str::prefix_eq(file, project_prefix, Str::len(project_prefix)))
                Str::delete_n_characters(file, Str::len(project_prefix));
        }
    } else {
        WRITE_TO(file, "(no file)");
    }
    WRITE_TO(PBUFF, "'");
    ProblemBuffer::copy_text(W);
    text_stream *paraphrase = file;
    #ifdef DESCRIBE_SOURCE_FILE_PROBLEMS_CALLBACK
    paraphrase = DESCRIBE_SOURCE_FILE_PROBLEMS_CALLBACK(paraphrase, referred, file);
    #endif
    WRITE_TO(PBUFF, "' %c%S%c%S%c%d%c",
        SOURCE_REF_CHAR, paraphrase,
        SOURCE_REF_CHAR, file,
        SOURCE_REF_CHAR, Wordings::location(W).line_number,
        SOURCE_REF_CHAR);
    if ((redirected_sentence) &&
        (redirected_to_A) &&
        (redirected_to_B) &&
        (Wordings::eq(Node::get_text(redirected_sentence), W))) {
        WRITE_TO(PBUFF, " (which asserts that ");
        ProblemBuffer::copy_source_reference(
            Node::get_text(redirected_to_A));
        WRITE_TO(PBUFF, " is/are ");
        ProblemBuffer::copy_source_reference(
            Node::get_text(redirected_to_B));
        WRITE_TO(PBUFF, ")");
    }
    DISCARD_TEXT(file)
}

void ProblemBuffer::copy_file_reference?Usage of ProblemBuffer::copy_file_reference:
Problems, Level 2 - §13.1.1(text_stream *file_ref, int line) {
    TEMPORARY_TEXT(file)
    WRITE_TO(file, "%S", file_ref);
    pathname *proj = HTML::get_link_abbreviation_path();
    if (proj) {
        TEMPORARY_TEXT(project_prefix)
        WRITE_TO(project_prefix, "%p", proj);
        if (Str::prefix_eq(file, project_prefix, Str::len(project_prefix)))
            Str::delete_n_characters(file, Str::len(project_prefix));
        DISCARD_TEXT(project_prefix)
    } else {
        WRITE_TO(file, "(no file)");
    }
    text_stream *paraphrase = file;
    #ifdef DESCRIBE_SOURCE_FILE_PROBLEMS_CALLBACK
    paraphrase = DESCRIBE_SOURCE_FILE_PROBLEMS_CALLBACK(paraphrase, NULL, file);
    #endif
    WRITE_TO(PBUFF, " %c%S%c%S%c%d%c",
        SOURCE_REF_CHAR, paraphrase,
        SOURCE_REF_CHAR, file,
        SOURCE_REF_CHAR, line,
        SOURCE_REF_CHAR);
    DISCARD_TEXT(file)
}

§5. Once the error message is fully constructed, we will want to output it to a file: in fact, by default it will go in three directions, to stderr, to the debugging log and of course to the problems file. The main thing is to word-wrap it, since it is likely to be a paragraph-sized chunk of text, not a single line. The unprintable SOURCE_REF_CHAR and FORCE_NEW_PARA_CHAR are simply filtered out for plain text output: for HTML, they are dealt with elsewhere.

define PROBLEM_WORD_WRAP_WIDTH 80

int problem_count_at_last_in = 1;
text_stream problems_file_struct;  The actual report of Problems file
text_stream *problems_file = &problems_file_struct;  As a text_stream *
int problems_file_active = FALSE;  Currently in use
int currently_issuing_a_warning = FALSE;

#ifndef PROBLEMS_HTML_EMITTER
#define PROBLEMS_HTML_EMITTER PUT_TO
#endif

void ProblemBuffer::output_problem_buffer_to?Usage of ProblemBuffer::output_problem_buffer_to:
§6(OUTPUT_STREAM, int indentation) {
    int line_width = 0, html_flag = FALSE;
    int sig_mode = FALSE, break_width = PROBLEM_WORD_WRAP_WIDTH; filename *fallback = NULL;
    #ifdef FORMAT_CONSOLE_PROBLEMS_CALLBACK
    FORMAT_CONSOLE_PROBLEMS_CALLBACK(&sig_mode, &break_width, &fallback);
    #endif
    if (OUT == problems_file) html_flag = TRUE;

    if (sig_mode == FALSE)
        for (int k=0; k<indentation; k++) { WRITE("  "); line_width+=2; }
    TEMPORARY_TEXT(first)
    TEMPORARY_TEXT(second)
    TEMPORARY_TEXT(third)
    Extract details of the first source code reference, if there is one5.1;

    int i = 0;
    In HTML mode, convert drawing-your-attention arrows5.2;
    In SIG mode, convert drawing-your-attention arrows5.3;
    for (; i<Str::len(PBUFF); i++) {
        inchar32_t c = Str::get_at(PBUFF, i);
        In plain text mode, remove bold and italic HTML tags5.4;
        if ((html_flag == FALSE) && (c == SOURCE_REF_CHAR))
            Issue plain text paraphrase of source reference5.5
        else Output single character of problem message5.6;
    }
    if (html_flag) HTML_CLOSE("p")
    else WRITE("\n");

    DISCARD_TEXT(first)
    DISCARD_TEXT(second)
    DISCARD_TEXT(third)
}

§5.1. In "silence is golden" mode, we will need a filename and line number to report at: we pick this out as the first source reference in the message.

Extract details of the first source code reference, if there is one5.1 =

    for (int i=0, f=0, L=Str::len(PBUFF); i<L; i++) {
        inchar32_t c = Str::get_at(PBUFF, i);
        if (c == SOURCE_REF_CHAR) f++;
        else if (f == 1) PUT_TO(first, c);
        else if (f == 2) PUT_TO(second, c);
        else if (f == 3) PUT_TO(third, c);
    }

• This code is used in §5.

§5.2. The plain text "may I draw your attention to the following paragraph" marker,

>--> Which looks like this.

is converted into a suitable CSS-styled HTML paragraph with hanging indentation. And similarly for >++>, used to mark continuations.

Note that in HTML, this always opens one paragraph tag.

In HTML mode, convert drawing-your-attention arrows5.2 =

    if ((html_flag) && (Str::includes_wide_string_at(PBUFF, U">-->", i))) {
        if (problem_count > problem_count_at_last_in) {
            HTML_TAG("hr");
        }
        HTML_OPEN_WITH("p", "class=\"hang\"");
        if (currently_issuing_a_warning) WRITE("<b>Warning.</b> ");
        else WRITE("<b>Problem.</b> ");
        i = 4;
    } else if (Str::includes_wide_string_at(PBUFF, U">++>", i)) {
        if (html_flag) HTML_OPEN_WITH("p", "class=\"in2\"") else WRITE("  ");
        i = 4;
    } else if (Str::includes_wide_string_at(PBUFF, U">--->", i)) {
        if (html_flag) {
            HTML_CLOSE("p"); HTML_TAG("hr");
        }
        problem_count_at_last_in = problem_count+1;
        i = 5;
    } else if (Str::includes_wide_string_at(PBUFF, U">+++>", i)) {
        if (html_flag) HTML_OPEN_WITH("p", "halftightin3\"") else WRITE("  ");
        i = 5;
    } else if (Str::includes_wide_string_at(PBUFF, U">++++>", i)) {
        if (html_flag) HTML_OPEN_WITH("p", "class=\"tightin3\"") else WRITE("  ");
        i = 6;
    } else if (html_flag) HTML_OPEN("p");

• This code is used in §5.

§5.3. In SIG mode, convert drawing-your-attention arrows5.3 =

    if ((sig_mode) && (Str::includes_wide_string_at(PBUFF, U">-->", i))) {
        WRITE("\033[1m");
        if (Str::len(second) > 0) {
            WRITE("%p%S:%S: ", HTML::get_link_abbreviation_path(), second, third);
        } else if (fallback) {
            WRITE("%f:1: ", fallback);
        }
        WRITE("\033[31m");
        WRITE("problem: ");
        WRITE("\033[0m");
        i = 4;
    }

• This code is used in §5.

§5.4. The problem messages are put together (by Level 2 below) in a plain text way, but with a little formatting included: in particular, they contain HTML-style <i>, <b> and <span> tags, which the following code strips out when writing to plain text format.

In plain text mode, remove bold and italic HTML tags5.4 =

    if (html_flag == FALSE) {
        if (c == PROTECTED_LT_CHAR) {
            while ((i<Str::len(PBUFF)) && (Str::get_at(PBUFF, i) != PROTECTED_GT_CHAR)) i++;
            continue;
        }
        if ((c == '<') &&
                ((Str::includes_wide_string_at_insensitive(PBUFF, U"<i>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<b>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<img>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<a>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<font>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<i ", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<b ", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<img ", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<a ", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<font ", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"<span ", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"</i>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"</b>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"</img>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"</a>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"</span>", i)) ||
                (Str::includes_wide_string_at_insensitive(PBUFF, U"</font>", i)))) {
            while ((i<Str::len(PBUFF)) && (Str::get_at(PBUFF, i) != '>')) i++;
            continue;
        }
    }

• This code is used in §5.

§5.5. Okay, so the format for a source reference here is:

    XparaphraseXfilenameXnumberX

e.g., Xmain textXsource/story.niX102, where X is the unprintable SOURCE_REF_CHAR. The counter i is at the first X, and we must now convert this to something fit for printing to stdout, finishing up with i pointing to the last X.

We always use the paraphrase, not the filename, on stdout because (i) that's slightly easier to understand for the user, but more importantly (ii) it makes the output the same on all platforms when only main text and Standard Rules are referred to, and that simplifies intest and the Test Suite quite a bit, because we don't have to worry about trivial differences between OS X and Windows caused by the slashes going the wrong way, and so on.

Issue plain text paraphrase of source reference5.5 =

    WRITE("("); line_width++;
    while (Str::get_at(PBUFF, ++i) != SOURCE_REF_CHAR)
        Output single character of problem message5.6;
    while (Str::get_at(PBUFF, ++i) != SOURCE_REF_CHAR) ;
    WRITE(", line "); line_width += 7;
    while (Str::get_at(PBUFF, ++i) != SOURCE_REF_CHAR)
        Output single character of problem message5.6;
    WRITE(")"); line_width++;

• This code is used in §5.

§5.6. Output single character of problem message5.6 =

    c = Str::get_at(PBUFF, i);
    if (Characters::is_whitespace(c)) {  this starts a run of whitespace
        int l = i; while (Characters::is_whitespace(Str::get_at(PBUFF, l))) l++;
        if (Str::get_at(PBUFF, l) == 0) break;  omit any trailing spaces
        i = l - 1;  skip to final whitespace character of the run
        if (html_flag) PROBLEMS_HTML_EMITTER(OUT, ' ');
        else In plain text mode, wrap the line or print a space as necessary5.6.1;
    } else {
        line_width++;
        if (c == PROTECTED_LT_CHAR) PUT('<');
        else if (c == PROTECTED_GT_CHAR) PUT('>');
        else if (c == PROTECTED_QUOT_CHAR) PUT('"');
        else if (html_flag) PROBLEMS_HTML_EMITTER(OUT, c);
        else if ((c != SOURCE_REF_CHAR) && (c != FORCE_NEW_PARA_CHAR)) WRITE("%c", c);
    }

• This code is used in §5, §5.5 (twice).

§5.6.1. At this point, l is the position of the first non-whitespace character after the sequence of whitespace.

In plain text mode, wrap the line or print a space as necessary5.6.1 =

    int word_width = 0;
    while ((!Characters::is_whitespace(Str::get_at(PBUFF, l))) && (Str::get_at(PBUFF, l) != 0)
        && (Str::get_at(PBUFF, l) != SOURCE_REF_CHAR))
        l++, word_width++;
    if (line_width + word_width + 1 >= break_width) {
        WRITE("\n"); line_width = 0;
        for (l=0; l<indentation+1; l++) { line_width+=2; WRITE("  "); }
    } else {
        WRITE(" "); line_width++;
    }

• This code is used in §5.6.

§6. The following allows us to route individual messages to only one output of our choice.

text_stream *redirected_problem_text = NULL;  Current destination of problem message text
text_stream *ProblemBuffer::redirect_problem_stream(text_stream *S) {
    redirected_problem_text = S;
    return S;
}

void ProblemBuffer::output_problem_buffer?Usage of ProblemBuffer::output_problem_buffer:
Problems, Level 2 - §3.1, §10(int indentation) {
    if (redirected_problem_text == NULL) {
        ProblemBuffer::output_problem_buffer_to(problems_file, indentation);
        WRITE_TO(problems_file, "\n");
        ProblemBuffer::output_problem_buffer_to(STDERR, indentation);
        STREAM_FLUSH(STDERR);
        WRITE_TO(DL, "\n");
        ProblemBuffer::output_problem_buffer_to(DL, indentation);
        WRITE_TO(DL, "\n");
    } else {
        ProblemBuffer::output_problem_buffer_to(redirected_problem_text, indentation);
    }
}

§7. Problems report and index. That gives us enough infrastructure to produce the final report. Note the use of error redirection to in order to put pseudo-problem messages — actually informational — into the report. In the case where the run was successful and there we no Problem messages, we have to be careful to reset problem_count — it will have been increased by the issuing of these pseudo-problems, and we need it to remain 0 so that main() can finally return back to the operating system without an error code.

int tail_of_report_written = FALSE;
void ProblemBuffer::write_reports?Usage of ProblemBuffer::write_reports:
Problems, Level 3 - §3, §11(int disaster_struck) {
    if (tail_of_report_written) return;
    tail_of_report_written = TRUE;

    crash_on_all_problems = FALSE;
    #ifdef INFORMATIONAL_ADDENDA_PROBLEMS_CALLBACK
    int pc = problem_count;
    INFORMATIONAL_ADDENDA_PROBLEMS_CALLBACK(disaster_struck, problem_count);
    problem_count = pc;
    #endif
    if (problems_file_active) {
        #ifdef END_PROBLEM_FILE_PROBLEMS_CALLBACK
        END_PROBLEM_FILE_PROBLEMS_CALLBACK(problems_file);
        #endif
        #ifndef END_PROBLEM_FILE_PROBLEMS_CALLBACK
        HTML::footer(problems_file);
        #endif
    }
}