mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

	Commit message (Expand)	Author	Age	Files	Lines
*	5852	Kartik Agaram	2020-01-01	1	-0/+246
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<span class="Delimiter">:(before &quot;End Primitive Recipe Declarations&quot;)</span>
_BROWSE_TRACE<span class="Delimiter">,</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Numbers&quot;)</span>
Recipe_ordinal[<span class="Constant">&quot;$browse-trace&quot;</span>] = _BROWSE_TRACE<span class="Delimiter">;</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Implementations&quot;)</span>
case _BROWSE_TRACE: <span class="Delimiter">{</span>
  start_trace_browser<span class="Delimiter">();</span>
  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(before &quot;End Globals&quot;)</span>
set&lt;long long int&gt; Visible<span class="Delimiter">;</span>
long long int Top_of_screen = <span class="Constant">0</span><span class="Delimiter">;</span>
long long int Last_printed_row = <span class="Constant">0</span><span class="Delimiter">;</span>
map&lt;int<span class="Delimiter">,</span> long long int&gt; Trace_index<span class="Delimiter">;</span>  <span class="Comment">// screen row -&gt; trace index</span>

<span class="Delimiter">:(code)</span>
void start_trace_browser<span class="Delimiter">()</span> <span class="Delimiter">{</span>
  if <span class="Delimiter">(</span>!Trace_stream<span class="Delimiter">)</span> <span class="Identifier">return</span><span class="Delimiter">;</span>
  cerr &lt;&lt; <span class="Constant">&quot;computing depth to display</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span><span class="Delimiter">;</span>
  long long int min_depth = <span class="Constant">9999</span><span class="Delimiter">;</span>
  for <span class="Delimiter">(</span>long long int i = <span class="Constant">0</span><span class="Delimiter">;</span> i &lt; SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    trace_line&amp; curr_line = Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">);</span>
    if <span class="Delimiter">(</span>curr_line<span class="Delimiter">.</span>depth == <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
    if <span class="Delimiter">(</span>curr_line<span class="Delimiter">.</span>depth &lt; min_depth<span class="Delimiter">)</span> min_depth = curr_line<span class="Delimiter">.</span>depth<span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  cerr &lt;&lt; <span class="Constant">&quot;depth is &quot;</span> &lt;&lt; min_depth &lt;&lt; <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
  cerr &lt;&lt; <span class="Constant">&quot;computing lines to display</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span><span class="Delimiter">;</span>
  for <span class="Delimiter">(</span>long long int i = <span class="Constant">0</span><span class="Delimiter">;</span> i &lt; SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    if <span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">).</span>depth == min_depth<span class="Delimiter">)</span>
      Visible<span class="Delimiter">.</span>insert<span class="Delimiter">(</span>i<span class="Delimiter">);</span>
  <span class="Delimiter">}</span>
  tb_init<span class="Delimiter">();</span>
  Display_row = Display_column = <span class="Constant">0</span><span class="Delimiter">;</span>
  tb_event event<span class="Delimiter">;</span>
  Top_of_screen = <span class="Constant">0</span><span class="Delimiter">;</span>
  refresh_screen_rows<span class="Delimiter">();</span>
  while <span class="Delimiter">(</span><span class="Constant">true</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    render<span class="Delimiter">();</span>
    do <span class="Delimiter">{</span>
      tb_poll_event<span class="Delimiter">(</span>&amp;event<span class="Delimiter">);</span>
    <span class="Delimiter">}</span> while <span class="Delimiter">(</span>event<span class="Delimiter">.</span>type != TB_EVENT_KEY<span class="Delimiter">);</span>
    long long int key = event<span class="Delimiter">.</span>key ? event<span class="Delimiter">.</span>key : event<span class="Delimiter">.</span>ch<span class="Delimiter">;</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'q'</span> || key == <span class="Constant">'Q'</span><span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'j'</span> || key == TB_KEY_ARROW_DOWN<span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// move cursor one line down</span>
      if <span class="Delimiter">(</span>Display_row &lt; Last_printed_row<span class="Delimiter">)</span> ++Display_row<span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'k'</span> || key == TB_KEY_ARROW_UP<span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// move cursor one line up</span>
      if <span class="Delimiter">(</span>Display_row &gt; <span class="Constant">0</span><span class="Delimiter">)</span> --Display_row<span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'H'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// move cursor to top of screen</span>
      Display_row = <span class="Constant">0</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'M'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// move cursor to center of screen</span>
      Display_row = tb_height<span class="Delimiter">()</span>/<span class="Constant">2</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'L'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// move cursor to bottom of screen</span>
      Display_row = tb_height<span class="Delimiter">()</span>-<span class="Constant">1</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'J'</span> || key == TB_KEY_PGDN<span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// page-down</span>
      if <span class="Delimiter">(</span>Trace_index<span class="Delimiter">.</span>find<span class="Delimiter">(</span>tb_height<span class="Delimiter">()</span>-<span class="Constant">1</span><span class="Delimiter">)</span> != Trace_index<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Delimiter">{</span>
        Top_of_screen = Trace_index[tb_height<span class="Delimiter">()</span>-<span class="Constant">1</span>]+<span class="Constant">1</span><span class="Delimiter">;</span>
        refresh_screen_rows<span class="Delimiter">();</span>
      <span class="Delimiter">}</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'K'</span> || key == TB_KEY_PGUP<span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// page-up is more convoluted</span>
<span class="CommentedCode">//?       tb_shutdown(); //? 1</span>
<span class="CommentedCode">//?       cerr &lt;&lt; &quot;page-up: Top_of_screen is currently &quot; &lt;&lt; Top_of_screen &lt;&lt; '\n'; //? 1</span>
      for <span class="Delimiter">(</span>int screen_row = tb_height<span class="Delimiter">();</span> screen_row &gt; <span class="Constant">0</span> &amp;&amp; Top_of_screen &gt; <span class="Constant">0</span><span class="Delimiter">;</span> --screen_row<span class="Delimiter">)</span> <span class="Delimiter">{</span>
        --Top_of_screen<span class="Delimiter">;</span>
        if <span class="Delimiter">(</span>Top_of_screen &lt;= <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
        while <span class="Delimiter">(</span>Top_of_screen &gt; <span class="Constant">0</span> &amp;&amp; Visible<span class="Delimiter">.</span>find<span class="Delimiter">(</span>Top_of_screen<span class="Delimiter">)</span> == Visible<span class="Delimiter">.</span>end<span class="Delimiter">())</span>
          --Top_of_screen<span class="Delimiter">;</span>
<span class="CommentedCode">//?         cerr &lt;&lt; &quot;now &quot; &lt;&lt; Top_of_screen &lt;&lt; '\n'; //? 1</span>
      <span class="Delimiter">}</span>
<span class="CommentedCode">//?       exit(0); //? 1</span>
      if <span class="Delimiter">(</span>Top_of_screen &gt; <span class="Constant">0</span><span class="Delimiter">)</span>
        refresh_screen_rows<span class="Delimiter">();</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == <span class="Constant">'G'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// go to bottom of screen; largely like page-up, interestingly</span>
      Top_of_screen = SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">)</span>-<span class="Constant">1</span><span class="Delimiter">;</span>
      for <span class="Delimiter">(</span>int screen_row = tb_height<span class="Delimiter">();</span> screen_row &gt; <span class="Constant">0</span> &amp;&amp; Top_of_screen &gt; <span class="Constant">0</span><span class="Delimiter">;</span> --screen_row<span class="Delimiter">)</span> <span class="Delimiter">{</span>
        --Top_of_screen<span class="Delimiter">;</span>
        if <span class="Delimiter">(</span>Top_of_screen &lt;= <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
        while <span class="Delimiter">(</span>Top_of_screen &gt; <span class="Constant">0</span> &amp;&amp; Visible<span class="Delimiter">.</span>find<span class="Delimiter">(</span>Top_of_screen<span class="Delimiter">)</span> == Visible<span class="Delimiter">.</span>end<span class="Delimiter">())</span>
          --Top_of_screen<span class="Delimiter">;</span>
      <span class="Delimiter">}</span>
      refresh_screen_rows<span class="Delimiter">();</span>
      <span class="Comment">// move cursor to bottom</span>
      Display_row = Last_printed_row<span class="Delimiter">;</span>
      refresh_screen_rows<span class="Delimiter">();</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == TB_KEY_CARRIAGE_RETURN<span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// expand lines under current by one level</span>
<span class="CommentedCode">//?       tb_shutdown();</span>
      assert<span class="Delimiter">(</span>Trace_index<span class="Delimiter">.</span>find<span class="Delimiter">(</span>Display_row<span class="Delimiter">)</span> != Trace_index<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
      long long int start_index = Trace_index[Display_row]<span class="Delimiter">;</span>
<span class="CommentedCode">//?       cerr &lt;&lt; &quot;start_index is &quot; &lt;&lt; start_index &lt;&lt; '\n';</span>
      long long int index = <span class="Constant">0</span><span class="Delimiter">;</span>
      <span class="Comment">// simultaneously compute end_index and min_depth</span>
      int min_depth = <span class="Constant">9999</span><span class="Delimiter">;</span>
      for <span class="Delimiter">(</span>index = start_index+<span class="Constant">1</span><span class="Delimiter">;</span> index &lt; SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">);</span> ++index<span class="Delimiter">)</span> <span class="Delimiter">{</span>
        if <span class="Delimiter">(</span>Visible<span class="Delimiter">.</span>find<span class="Delimiter">(</span>index<span class="Delimiter">)</span> != Visible<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
        trace_line&amp; curr_line = Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">.</span>at<span class="Delimiter">(</span>index<span class="Delimiter">);</span>
        if <span class="Delimiter">(</span>curr_line<span class="Delimiter">.</span>depth == <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
        assert<span class="Delimiter">(</span>curr_line<span class="Delimiter">.</span>depth &gt; Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">.</span>at<span class="Delimiter">(</span>start_index<span class="Delimiter">).</span>depth<span class="Delimiter">);</span>
        if <span class="Delimiter">(</span>curr_line<span class="Delimiter">.</span>depth &lt; min_depth<span class="Delimiter">)</span> min_depth = curr_line<span class="Delimiter">.</span>depth<span class="Delimiter">;</span>
      <span class="Delimiter">}</span>
<span class="CommentedCode">//?       cerr &lt;&lt; &quot;min_depth is &quot; &lt;&lt; min_depth &lt;&lt; '\n';</span>
      long long int end_index = index<span class="Delimiter">;</span>
<span class="CommentedCode">//?       cerr &lt;&lt; &quot;end_index is &quot; &lt;&lt; end_index &lt;&lt; '\n';</span>
      <span class="Comment">// mark as visible all intervening indices at min_depth</span>
      for <span class="Delimiter">(</span>index = start_index<span class="Delimiter">;</span> index &lt; end_index<span class="Delimiter">;</span> ++index<span class="Delimiter">)</span> <span class="Delimiter">{</span>
        trace_line&amp; curr_line = Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">.</span>at<span class="Delimiter">(</span>index<span class="Delimiter">);</span>
        if <span class="Delimiter">(</span>curr_line<span class="Delimiter">.</span>depth == min_depth<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="CommentedCode">//?           cerr &lt;&lt; &quot;adding &quot; &lt;&lt; index &lt;&lt; '\n';</span>
          Visible<span class="Delimiter">.</span>insert<span class="Delimiter">(</span>index<span class="Delimiter">);</span>
        <span class="Delimiter">}</span>
      <span class="Delimiter">}</span>
<span class="CommentedCode">//?       exit(0);</span>
      refresh_screen_rows<span class="Delimiter">();</span>
    <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>key == TB_KEY_BACKSPACE || key == TB_KEY_BACKSPACE2<span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// collapse all lines under current</span>
      assert<span class="Delimiter">(</span>Trace_index<span class="Delimiter">.</span>find<span class="Delimiter">(</span>Display_row<span class="Delimiter">)</span> != Trace_index<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
      long long int start_index = Trace_index[Display_row]<span class="Delimiter">;</span>
      long long int index = <span class="Constant">0</span><span class="Delimiter">;</span>
      <span class="Comment">// end_index is the next line at a depth same as or lower than start_index</span>
      int initial_depth = Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">.</span>at<span class="Delimiter">(</span>start_index<span class="Delimiter">).</span>depth<span class="Delimiter">;</span>
      for <span class="Delimiter">(</span>index = start_index+<span class="Constant">1</span><span class="Delimiter">;</span> index &lt; SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">);</span> ++index<span class="Delimiter">)</span> <span class="Delimiter">{</span>
        if <span class="Delimiter">(</span>Visible<span class="Delimiter">.</span>find<span class="Delimiter">(</span>index<span class="Delimiter">)</span> == Visible<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
        trace_line&amp; curr_line = Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">.</span>at<span class="Delimiter">(</span>index<span class="Delimiter">);</span>
        if <span class="Delimiter">(</span>curr_line<span class="Delimiter">.</span>depth == <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
        if <span class="Delimiter">(</span>curr_line<span class="Delimiter">.</span>depth &lt;= initial_depth<span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
      <span class="Delimiter">}</span>
      long long int end_index = index<span class="Delimiter">;</span>
      <span class="Comment">// mark as visible all intervening indices at min_depth</span>
      for <span class="Delimiter">(</span>index = start_index+<span class="Constant">1</span><span class="Delimiter">;</span> index &lt; end_index<span class="Delimiter">;</span> ++index<span class="Delimiter">)</span> <span class="Delimiter">{</span>
        Visible<span class="Delimiter">.</span>erase<span class="Delimiter">(</span>index<span class="Delimiter">);</span>
      <span class="Delimiter">}</span>
      refresh_screen_rows<span class="Delimiter">();</span>
    <span class="Delimiter">}</span>
  <span class="Delimiter">}</span>
  tb_shutdown<span class="Delimiter">();</span>
<span class="Delimiter">}</span>

<span class="Comment">// update Trace_indices for each screen_row on the basis of Top_of_screen and Visible</span>
void refresh_screen_rows<span class="Delimiter">()</span> <span class="Delimiter">{</span>
  long long int screen_row = <span class="Constant">0</span><span class="Delimiter">,</span> index = <span class="Constant">0</span><span class="Delimiter">;</span>
  Trace_index<span class="Delimiter">.</span>clear<span class="Delimiter">();</span>
  for <span class="Delimiter">(</span>screen_row = <span class="Constant">0</span><span class="Delimiter">,</span> index = Top_of_screen<span class="Delimiter">;</span> screen_row &lt; tb_height<span class="Delimiter">()</span> &amp;&amp; index &lt; SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">);</span> ++screen_row<span class="Delimiter">,</span> ++index<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    <span class="Comment">// skip lines without depth for now</span>
    while <span class="Delimiter">(</span>Visible<span class="Delimiter">.</span>find<span class="Delimiter">(</span>index<span class="Delimiter">)</span> == Visible<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Delimiter">{</span>
      ++index<span class="Delimiter">;</span>
      if <span class="Delimiter">(</span>index &gt;= SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">))</span> <span class="Identifier">goto</span> done<span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    assert<span class="Delimiter">(</span>index &lt; SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">));</span>
    Trace_index[screen_row] = index<span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
done:<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

void render<span class="Delimiter">()</span> <span class="Delimiter">{</span>
  long long int screen_row = <span class="Constant">0</span><span class="Delimiter">;</span>
  for <span class="Delimiter">(</span>screen_row = <span class="Constant">0</span><span class="Delimiter">;</span> screen_row &lt; tb_height<span class="Delimiter">();</span> ++screen_row<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    if <span class="Delimiter">(</span>Trace_index<span class="Delimiter">.</span>find<span class="Delimiter">(</span>screen_row<span class="Delimiter">)</span> == Trace_index<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
    trace_line&amp; curr_line = Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">.</span>at<span class="Delimiter">(</span>Trace_index[screen_row]<span class="Delimiter">);</span>
    ostringstream out<span class="Delimiter">;</span>
    out &lt;&lt; std::setw<span class="Delimiter">(</span><span class="Constant">4</span><span class="Delimiter">)</span> &lt;&lt; curr_line<span class="Delimiter">.</span>depth &lt;&lt; <span class="Constant">' '</span> &lt;&lt; curr_line<span class="Delimiter">.</span>label &lt;&lt; <span class="Constant">&quot;: &quot;</span> &lt;&lt; curr_line<span class="Delimiter">.</span>contents<span class="Delimiter">;</span>
    if <span class="Delimiter">(</span>screen_row &lt; tb_height<span class="Delimiter">()</span>-<span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      long long int delta = lines_hidden<span class="Delimiter">(</span>screen_row<span class="Delimiter">);</span>
      <span class="Comment">// home-brew escape sequence for red</span>
      if <span class="Delimiter">(</span>delta &gt; <span class="Constant">999</span><span class="Delimiter">)</span> out &lt;&lt; <span class="Constant">&quot;{&quot;</span><span class="Delimiter">;</span>
      out &lt;&lt; <span class="Constant">&quot; (&quot;</span> &lt;&lt; lines_hidden<span class="Delimiter">(</span>screen_row<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;)&quot;</span><span class="Delimiter">;</span>
      if <span class="Delimiter">(</span>delta &gt; <span class="Constant">999</span><span class="Delimiter">)</span> out &lt;&lt; <span class="Constant">&quot;}&quot;</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    render_line<span class="Delimiter">(</span>screen_row<span class="Delimiter">,</span> out<span class="Delimiter">.</span>str<span class="Delimiter">());</span>
  <span class="Delimiter">}</span>
  <span class="Comment">// clear rest of screen</span>
  Last_printed_row = screen_row-<span class="Constant">1</span><span class="Delimiter">;</span>
  for <span class="Delimiter">(;</span> screen_row &lt; tb_height<span class="Delimiter">();</span> ++screen_row<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    render_line<span class="Delimiter">(</span>screen_row<span class="Delimiter">,</span> <span class="Constant">&quot;~&quot;</span><span class="Delimiter">);</span>
  <span class="Delimiter">}</span>
  <span class="Comment">// move cursor back to display row at the end</span>
  tb_set_cursor<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">,</span> Display_row<span class="Delimiter">);</span>
  tb_present<span class="Delimiter">();</span>
<span class="Delimiter">}</span>

long long int lines_hidden<span class="Delimiter">(</span>long long int screen_row<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  assert<span class="Delimiter">(</span>Trace_index<span class="Delimiter">.</span>find<span class="Delimiter">(</span>screen_row<span class="Delimiter">)</span> != Trace_index<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
  if <span class="Delimiter">(</span>Trace_index<span class="Delimiter">.</span>find<span class="Delimiter">(</span>screen_row+<span class="Constant">1</span><span class="Delimiter">)</span> == Trace_index<span class="Delimiter">.</span>end<span class="Delimiter">())</span>
    <span class="Identifier">return</span> SIZE<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>past_lines<span class="Delimiter">)</span>-Trace_index[screen_row]<span class="Delimiter">;</span>
  else
    <span class="Identifier">return</span> Trace_index[screen_row+<span class="Constant">1</span>] - Trace_index[screen_row]<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

void render_line<span class="Delimiter">(</span>int screen_row<span class="Delimiter">,</span> const string&amp; s<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  long long int col = <span class="Constant">0</span><span class="Delimiter">;</span>
  int color = TB_WHITE<span class="Delimiter">;</span>
  for <span class="Delimiter">(</span>col = <span class="Constant">0</span><span class="Delimiter">;</span> col &lt; tb_width<span class="Delimiter">()</span> &amp;&amp; col &lt; SIZE<span class="Delimiter">(</span>s<span class="Delimiter">);</span> ++col<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    char c = s<span class="Delimiter">.</span>at<span class="Delimiter">(</span>col<span class="Delimiter">);</span>  <span class="Comment">// todo: unicode</span>
    if <span class="Delimiter">(</span>c == <span class="cSpecial">'\n'</span><span class="Delimiter">)</span> c = <span class="Constant">';'</span><span class="Delimiter">;</span>  <span class="Comment">// replace newlines with semi-colons</span>
    <span class="Comment">// escapes. hack: can't start a line with them.</span>
    if <span class="Delimiter">(</span>c == <span class="Constant">'{'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span> color = <span class="Comment">/*</span><span class="Comment">red</span><span class="Comment">*/</span><span class="Constant">1</span><span class="Delimiter">;</span> c = <span class="Constant">' '</span><span class="Delimiter">;</span> <span class="Delimiter">}</span>
    if <span class="Delimiter">(</span>c == <span class="Constant">'}'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span> color = TB_WHITE<span class="Delimiter">;</span> c = <span class="Constant">' '</span><span class="Delimiter">;</span> <span class="Delimiter">}</span>
    tb_change_cell<span class="Delimiter">(</span>col<span class="Delimiter">,</span> screen_row<span class="Delimiter">,</span> c<span class="Delimiter">,</span> color<span class="Delimiter">,</span> TB_BLACK<span class="Delimiter">);</span>
  <span class="Delimiter">}</span>
  for <span class="Delimiter">(;</span> col &lt; tb_width<span class="Delimiter">();</span> ++col<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    tb_change_cell<span class="Delimiter">(</span>col<span class="Delimiter">,</span> screen_row<span class="Delimiter">,</span> <span class="Constant">' '</span><span class="Delimiter">,</span> TB_WHITE<span class="Delimiter">,</span> TB_BLACK<span class="Delimiter">);</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>
</pre>
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