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<span class="Comment">//: Everything this project/binary supports.</span>
<span class="Comment">//: This should give you a sense for what to look forward to in later layers.</span>
<span class="Delimiter">:(before "End Commandline Parsing")</span>
<span class="Normal">if</span> <span class="Delimiter">(</span>argc <= <span class="Constant">1</span> || is_equal<span class="Delimiter">(</span>argv[<span class="Constant">1</span>]<span class="Delimiter">,</span> <span class="Constant">"--help"</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span class="Comment">//: this is the functionality later layers will provide</span>
<span class="Comment">// currently no automated tests for commandline arg parsing</span>
<span class="Normal">if</span> <span class="Delimiter">(</span>argc <= <span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
cerr << <span class="Constant">"Please provide a Mu program to run.</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">"</span><span class="cSpecial">\n</span><span class="Constant">"</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>
cerr << <span class="Constant">"Usage:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu [options] [test] [files]</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">"or:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu [options] [test] [files] -- [ingredients for function/recipe 'main']</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">"Square brackets surround optional arguments.</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">"</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">"Examples:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To load files and run 'main':</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu file1.mu file2.mu ...</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To run 'main' and dump a trace of all operations at the end:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu --trace file1.mu file2.mu ...</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To run all tests:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu test</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To load files and then run all tests:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu test file1.mu file2.mu ...</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To run a single Mu scenario:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu test file1.mu file2.mu ... scenario</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To run a single Mu scenario and dump a trace at the end:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu --trace test file1.mu file2.mu ... scenario</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To load files and run only the tests in explicitly loaded files (for apps):</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu --test-only-app test file1.mu file2.mu ...</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To load all files with a numeric prefix in a directory:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu directory1 directory2 ...</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" You can test directories just like files.</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu test directory1 directory2 ...</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To pass ingredients to a mu program, provide them after '--':</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu file_or_dir1 file_or_dir2 ... -- ingredient1 ingredient2 ...</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">"</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" To browse a trace generated by a previous run:</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<< <span class="Constant">" mu browse-trace file</span><span class="cSpecial">\n</span><span class="Constant">"</span>
<span class="Delimiter">;</span>
<span class="Identifier">return</span> <span class="Constant">0</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Comment">//: Support for option parsing.</span>
<span class="Comment">//: Options always begin with '--' and are always the first arguments. An</span>
<span class="Comment">//: option will never follow a non-option.</span>
<span class="Delimiter">:(before "End Commandline Parsing")</span>
<span class="Normal">char</span>** arg = &argv[<span class="Constant">1</span>]<span class="Delimiter">;</span>
<span class="Normal">while</span> <span class="Delimiter">(</span>argc > <span class="Constant">1</span> && starts_with<span class="Delimiter">(</span>*arg<span class="Delimiter">,</span> <span class="Constant">"--"</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span class="Normal">if</span> <span class="Delimiter">(</span><span class="Constant">false</span><span class="Delimiter">)</span>
<span class="Delimiter">;</span> <span class="Comment">// no-op branch just so any further additions can consistently always start with 'else'</span>
<span class="Comment">// End Commandline Options(*arg)</span>
<span class="Normal">else</span>
cerr << <span class="Constant">"skipping unknown option "</span> << *arg << <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
--argc<span class="Delimiter">;</span> ++argv<span class="Delimiter">;</span> ++arg<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="SalientComment">//:: Helper function used by the above fragment of code (and later layers too,</span>
<span class="SalientComment">//:: who knows?).</span>
<span class="Comment">//: The :(code) directive appends function definitions to the end of the</span>
<span class="Comment">//: project. Regardless of where functions are defined, we can call them</span>
<span class="Comment">//: anywhere we like as long as we format the function header in a specific</span>
<span class="Comment">//: way: put it all on a single line without indent, end the line with ') {'</span>
<span class="Comment">//: and no trailing whitespace. As long as functions uniformly start this</span>
<span class="Comment">//: way, our 'build' script contains a little command to automatically</span>
<span class="Comment">//: generate declarations for them.</span>
<span class="Delimiter">:(code)</span>
<span class="Normal">bool</span> is_equal<span class="Delimiter">(</span><span class="Normal">char</span>* s<span class="Delimiter">,</span> <span class="Normal">const</span> <span class="Normal">char</span>* lit<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Identifier">return</span> strncmp<span class="Delimiter">(</span>s<span class="Delimiter">,</span> lit<span class="Delimiter">,</span> strlen<span class="Delimiter">(</span>lit<span class="Delimiter">))</span> == <span class="Constant">0</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Normal">bool</span> starts_with<span class="Delimiter">(</span><span class="Normal">const</span> string& s<span class="Delimiter">,</span> <span class="Normal">const</span> string& pat<span class="Delimiter">)</span> <span class="Delimiter">{</span>
string::const_iterator a=s<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> b=pat<span class="Delimiter">.</span>begin<span class="Delimiter">();</span>
<span class="Normal">for</span> <span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">nada</span><span class="Comment">*/</span><span class="Delimiter">;</span> a!=s<span class="Delimiter">.</span>end<span class="Delimiter">()</span> && b!=pat<span class="Delimiter">.</span>end<span class="Delimiter">();</span> ++a<span class="Delimiter">,</span> ++b<span class="Delimiter">)</span>
<span class="Normal">if</span> <span class="Delimiter">(</span>*a != *b<span class="Delimiter">)</span> <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
<span class="Identifier">return</span> b == pat<span class="Delimiter">.</span>end<span class="Delimiter">();</span>
<span class="Delimiter">}</span>
<span class="Comment">//: I'll throw some style conventions here for want of a better place for them.</span>
<span class="Comment">//: As a rule I hate style guides. Do what you want, that's my motto. But since</span>
<span class="Comment">//: we're dealing with C/C++, the one big thing we want to avoid is undefined</span>
<span class="Comment">//: behavior. If a compiler ever encounters undefined behavior it can make</span>
<span class="Comment">//: your program do anything it wants.</span>
<span class="Comment">//:</span>
<span class="Comment">//: For reference, my checklist of undefined behaviors to watch out for:</span>
<span class="Comment">//: out-of-bounds access</span>
<span class="Comment">//: uninitialized variables</span>
<span class="Comment">//: use after free</span>
<span class="Comment">//: dereferencing invalid pointers: null, a new of size 0, others</span>
<span class="Comment">//:</span>
<span class="Comment">//: casting a large number to a type too small to hold it</span>
<span class="Comment">//:</span>
<span class="Comment">//: integer overflow</span>
<span class="Comment">//: division by zero and other undefined expressions</span>
<span class="Comment">//: left-shift by negative count</span>
<span class="Comment">//: shifting values by more than or equal to the number of bits they contain</span>
<span class="Comment">//: bitwise operations on signed numbers</span>
<span class="Comment">//:</span>
<span class="Comment">//: Converting pointers to types of different alignment requirements</span>
<span class="Comment">//: T* -> void* -> T*: defined</span>
<span class="Comment">//: T* -> U* -> T*: defined if non-function pointers and alignment requirements are same</span>
<span class="Comment">//: function pointers may be cast to other function pointers</span>
<span class="Comment">//:</span>
<span class="Comment">//: Casting a numeric value into a value that can't be represented by the target type (either directly or via static_cast)</span>
<span class="Comment">//:</span>
<span class="Comment">//: To guard against these, some conventions:</span>
<span class="Comment">//:</span>
<span class="Comment">//: 0. Initialize all primitive variables in functions and constructors.</span>
<span class="Comment">//:</span>
<span class="Comment">//: 1. Minimize use of pointers and pointer arithmetic. Avoid 'new' and</span>
<span class="Comment">//: 'delete' as far as possible. Rely on STL to perform memory management to</span>
<span class="Comment">//: avoid use-after-free issues (and memory leaks).</span>
<span class="Comment">//:</span>
<span class="Comment">//: 2. Avoid naked arrays to avoid out-of-bounds access. Never use operator[]</span>
<span class="Comment">//: except with map. Use at() with STL vectors and so on.</span>
<span class="Comment">//:</span>
<span class="Comment">//: 3. Valgrind all the things.</span>
<span class="Comment">//:</span>
<span class="Comment">//: 4. Avoid unsigned numbers. Not strictly an undefined-behavior issue, but</span>
<span class="Comment">//: the extra range doesn't matter, and it's one less confusing category of</span>
<span class="Comment">//: interaction gotchas to worry about.</span>
<span class="Comment">//:</span>
<span class="Comment">//: Corollary: don't use the size() method on containers, since it returns an</span>
<span class="Comment">//: unsigned and that'll cause warnings about mixing signed and unsigned,</span>
<span class="Comment">//: yadda-yadda. Instead use this macro below to perform an unsafe cast to</span>
<span class="Comment">//: signed. We'll just give up immediately if a container's ever too large.</span>
<span class="Comment">//: Basically, Mu is not concerned about this being a little slower than it</span>
<span class="Comment">//: could be. (<a href="https://gist.github.com/rygorous/e0f055bfb74e3d5f0af20690759de5a7)">https://gist.github.com/rygorous/e0f055bfb74e3d5f0af20690759de5a7)</a></span>
<span class="Comment">//:</span>
<span class="Comment">//: Addendum to corollary: We're going to uniformly use int everywhere, to</span>
<span class="Comment">//: indicate that we're oblivious to number size, and since Clang on 32-bit</span>
<span class="Comment">//: platforms doesn't yet support multiplication over 64-bit integers, and</span>
<span class="Comment">//: since multiplying two integers seems like a more common situation to end</span>
<span class="Comment">//: up in than integer overflow.</span>
<span class="Delimiter">:(before "End Includes")</span>
<span class="PreProc">#define SIZE(X) (assert((X)</span><span class="Delimiter">.</span><span class="PreProc">size() < (</span><span class="Constant">1LL</span><span class="PreProc"><<(</span><span class="Normal">sizeof</span><span class="PreProc">(</span><span class="Normal">int</span><span class="PreProc">)*</span><span class="Constant">8</span><span class="PreProc">-</span><span class="Constant">2</span><span class="PreProc">)))</span><span class="Delimiter">,</span><span class="PreProc"> </span><span class="Normal">static_cast</span><span class="PreProc"><</span><span class="Normal">int</span><span class="PreProc">>((X)</span><span class="Delimiter">.</span><span class="PreProc">size()))</span>
<span class="Comment">//: 5. Integer overflow is guarded against at runtime using the -ftrapv flag</span>
<span class="Comment">//: to the compiler, supported by Clang (GCC version only works sometimes:</span>
<span class="Comment">//: <a href="http://stackoverflow.com/questions/20851061/how-to-make-gcc-ftrapv-work).">http://stackoverflow.com/questions/20851061/how-to-make-gcc-ftrapv-work).</a></span>
<span class="Delimiter">:(before "atexit(teardown)")</span>
initialize_signal_handlers<span class="Delimiter">();</span> <span class="Comment">// not always necessary, but doesn't hurt</span>
<span class="CommentedCode">//? cerr << INT_MAX+1 << '\n'; // test overflow</span>
<span class="CommentedCode">//? assert(false); // test SIGABRT</span>
<span class="Delimiter">:(code)</span>
<span class="Comment">// based on <a href="https://spin.atomicobject.com/2013/01/13/exceptions-stack-traces-c">https://spin.atomicobject.com/2013/01/13/exceptions-stack-traces-c</a></span>
<span class="Normal">void</span> initialize_signal_handlers<span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span class="Normal">struct</span> sigaction action<span class="Delimiter">;</span>
bzero<span class="Delimiter">(</span>&action<span class="Delimiter">,</span> <span class="Normal">sizeof</span><span class="Delimiter">(</span>action<span class="Delimiter">));</span>
action<span class="Delimiter">.</span>sa_sigaction = dump_and_exit<span class="Delimiter">;</span>
sigemptyset<span class="Delimiter">(</span>&action<span class="Delimiter">.</span>sa_mask<span class="Delimiter">);</span>
sigaction<span class="Delimiter">(</span><span class="Constant">SIGABRT</span><span class="Delimiter">,</span> &action<span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">);</span> <span class="Comment">// assert() failure or integer overflow on linux (with -ftrapv)</span>
sigaction<span class="Delimiter">(</span><span class="Constant">SIGILL</span><span class="Delimiter">,</span> &action<span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">);</span> <span class="Comment">// integer overflow on OS X (with -ftrapv)</span>
<span class="Delimiter">}</span>
<span class="Normal">void</span> dump_and_exit<span class="Delimiter">(</span><span class="Normal">int</span> sig<span class="Delimiter">,</span> unused siginfo_t* dummy1<span class="Delimiter">,</span> unused <span class="Normal">void</span>* dummy2<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Normal">switch</span> <span class="Delimiter">(</span>sig<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Normal">case</span> <span class="Constant">SIGABRT</span>:
<span class="PreProc"> #ifndef __APPLE__</span>
cerr << <span class="Constant">"SIGABRT: might be an integer overflow if it wasn't an assert() failure</span><span class="cSpecial">\n</span><span class="Constant">"</span><span class="Delimiter">;</span>
_Exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span class="PreProc"> #endif</span>
<span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Normal">case</span> <span class="Constant">SIGILL</span>:
<span class="PreProc"> #ifdef __APPLE__</span>
cerr << <span class="Constant">"SIGILL: most likely caused by integer overflow</span><span class="cSpecial">\n</span><span class="Constant">"</span><span class="Delimiter">;</span>
_Exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span class="PreProc"> #endif</span>
<span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Normal">default</span>:
<span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Delimiter">}</span>
<span class="Delimiter">:(before "End Includes")</span>
<span class="PreProc">#include </span><span class="Constant"><signal.h></span>
<span class="Comment">//: For good measure we'll also enable SIGFPE.</span>
<span class="Delimiter">:(before "atexit(teardown)")</span>
feenableexcept<span class="Delimiter">(</span>FE_OVERFLOW | FE_UNDERFLOW<span class="Delimiter">);</span>
<span class="CommentedCode">//? assert(sizeof(int) == 4 && sizeof(float) == 4);</span>
<span class="CommentedCode">//? // | exp | mantissa</span>
<span class="CommentedCode">//? int smallest_subnormal = 0b00000000000000000000000000000001;</span>
<span class="CommentedCode">//? float smallest_subnormal_f = *reinterpret_cast<float*>(&smallest_subnormal);</span>
<span class="CommentedCode">//? cerr << "ε: " << smallest_subnormal_f << '\n';</span>
<span class="CommentedCode">//? cerr << "ε/2: " << smallest_subnormal_f/2 << " (underflow)\n"; // test SIGFPE</span>
<span class="Delimiter">:(before "End Includes")</span>
<span class="PreProc">#include </span><span class="Constant"><fenv.h></span>
<span class="Delimiter">:(code)</span>
<span class="PreProc">#ifdef __APPLE__</span>
<span class="Comment">// Public domain polyfill for feenableexcept on OS X</span>
<span class="Comment">// <a href="http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c">http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c</a></span>
<span class="Normal">int</span> feenableexcept <span class="Delimiter">(</span><span class="Normal">unsigned</span> <span class="Normal">int</span> excepts<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Normal">static</span> fenv_t fenv<span class="Delimiter">;</span>
<span class="Normal">unsigned</span> <span class="Normal">int</span> new_excepts = excepts & FE_ALL_EXCEPT<span class="Delimiter">;</span>
<span class="Normal">unsigned</span> <span class="Normal">int</span> old_excepts<span class="Delimiter">;</span>
<span class="Normal">if</span> <span class="Delimiter">(</span>fegetenv<span class="Delimiter">(</span>&fenv<span class="Delimiter">))</span> <span class="Identifier">return</span> -<span class="Constant">1</span><span class="Delimiter">;</span>
old_excepts = fenv<span class="Delimiter">.</span>__control & FE_ALL_EXCEPT<span class="Delimiter">;</span>
fenv<span class="Delimiter">.</span>__control &= ~new_excepts<span class="Delimiter">;</span>
fenv<span class="Delimiter">.</span>__mxcsr &= ~<span class="Delimiter">(</span>new_excepts << <span class="Constant">7</span><span class="Delimiter">);</span>
<span class="Identifier">return</span> fesetenv<span class="Delimiter">(</span>&fenv<span class="Delimiter">)</span> ? -<span class="Constant">1</span> : old_excepts<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="PreProc">#endif</span>
<span class="Comment">//: 6. Map's operator[] being non-const is fucking evil.</span>
<span class="Delimiter">:(before "Globals")</span> <span class="Comment">// can't generate prototypes for these</span>
<span class="Comment">// from <a href="http://stackoverflow.com/questions/152643/idiomatic-c-for-reading-from-a-const-map">http://stackoverflow.com/questions/152643/idiomatic-c-for-reading-from-a-const-map</a></span>
<span class="Normal">template</span><<span class="Normal">typename</span> T> <span class="Normal">typename</span> T::mapped_type& get<span class="Delimiter">(</span>T& map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>& key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Normal">typename</span> T::iterator iter<span class="Delimiter">(</span>map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">));</span>
assert<span class="Delimiter">(</span>iter != map<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span class="Identifier">return</span> iter<span class="Delimiter">-></span>second<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Normal">template</span><<span class="Normal">typename</span> T> <span class="Normal">typename</span> T::mapped_type <span class="Normal">const</span>& get<span class="Delimiter">(</span><span class="Normal">const</span> T& map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>& key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Normal">typename</span> T::const_iterator iter<span class="Delimiter">(</span>map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">));</span>
assert<span class="Delimiter">(</span>iter != map<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span class="Identifier">return</span> iter<span class="Delimiter">-></span>second<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Normal">template</span><<span class="Normal">typename</span> T> <span class="Normal">typename</span> T::mapped_type <span class="Normal">const</span>& put<span class="Delimiter">(</span>T& map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>& key<span class="Delimiter">,</span> <span class="Normal">typename</span> T::mapped_type <span class="Normal">const</span>& value<span class="Delimiter">)</span> <span class="Delimiter">{</span>
map[key] = value<span class="Delimiter">;</span>
<span class="Identifier">return</span> map[key]<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Normal">template</span><<span class="Normal">typename</span> T> <span class="Normal">bool</span> contains_key<span class="Delimiter">(</span>T& map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>& key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Identifier">return</span> map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">)</span> != map<span class="Delimiter">.</span>end<span class="Delimiter">();</span>
<span class="Delimiter">}</span>
<span class="Normal">template</span><<span class="Normal">typename</span> T> <span class="Normal">typename</span> T::mapped_type& get_or_insert<span class="Delimiter">(</span>T& map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>& key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Identifier">return</span> map[key]<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Comment">//: The contract: any container that relies on get_or_insert should never call</span>
<span class="Comment">//: contains_key.</span>
<span class="Comment">//: 7. istreams are a royal pain in the arse. You have to be careful about</span>
<span class="Comment">//: what subclass you try to putback into. You have to watch out for the pesky</span>
<span class="Comment">//: failbit and badbit. Just avoid eof() and use this helper instead.</span>
<span class="Delimiter">:(code)</span>
<span class="Normal">bool</span> has_data<span class="Delimiter">(</span>istream& in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span class="Identifier">return</span> in && !in<span class="Delimiter">.</span>eof<span class="Delimiter">();</span>
<span class="Delimiter">}</span>
<span class="Delimiter">:(before "End Includes")</span>
<span class="PreProc">#include </span><span class="Constant"><assert.h></span>
<span class="PreProc">#include </span><span class="Constant"><iostream></span>
<span class="Normal">using</span> std::istream<span class="Delimiter">;</span>
<span class="Normal">using</span> std::ostream<span class="Delimiter">;</span>
<span class="Normal">using</span> std::iostream<span class="Delimiter">;</span>
<span class="Normal">using</span> std::cin<span class="Delimiter">;</span>
<span class="Normal">using</span> std::cout<span class="Delimiter">;</span>
<span class="Normal">using</span> std::cerr<span class="Delimiter">;</span>
<span class="PreProc">#include </span><span class="Constant"><iomanip></span>
<span class="PreProc">#include </span><span class="Constant"><string.h></span>
<span class="PreProc">#include </span><span class="Constant"><string></span>
<span class="Normal">using</span> std::string<span class="Delimiter">;</span>
<span class="PreProc">#define unused __attribute__((unused))</span>
</pre>
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