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| author | Marshall Lochbaum <mwlochbaum@gmail.com> | 2021-08-11 17:21:31 -0400 |
|---|---|---|
| committer | Marshall Lochbaum <mwlochbaum@gmail.com> | 2021-08-11 17:25:04 -0400 |
| commit | 2afb23928e1984d475cc460e1672e8f6fa0e4dbe (patch) | |
| tree | ebd2cc514294d30b6fa4b36c2ee638326f06ef72 /docs/doc/assert.html | |
| parent | eac61ca02074c218667754d5f4ef562e780bae85 (diff) | |
Allow clicking on header to get fragment link
Diffstat (limited to 'docs/doc/assert.html')
| -rw-r--r-- | docs/doc/assert.html | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/docs/doc/assert.html b/docs/doc/assert.html index 7630f925..2e112283 100644 --- a/docs/doc/assert.html +++ b/docs/doc/assert.html @@ -4,7 +4,7 @@ <title>BQN: Assert</title> </head> <div class="nav">(<a href="https://github.com/mlochbaum/BQN">github</a>) / <a href="../index.html">BQN</a> / <a href="index.html">doc</a></div> -<h1 id="assert">Assert</h1> +<h1 id="assert"><a class="header" href="#assert">Assert</a></h1> <p>BQN takes the position that errors exist to indicate exceptional conditions that the developer of a given program didn't expect. However, the types of errors that BQN naturally checks for, such as mismatched shapes in Couple (<code><span class='Function'>≍</span></code>), aren't always enough to detect exceptional conditions. Issues like numeric values that don't make physical sense will slip right through. BQN makes it easy for a programmer to check for these sorts of problems by building in the primitive Assert, written <code><span class='Function'>!</span></code>. This function checks whether <code><span class='Value'>𝕩</span></code> matches <code><span class='Number'>1</span></code>: if it does, then it does nothing and returns <code><span class='Value'>𝕩</span></code>, and otherwise it gives an error.</p> <a class="replLink" title="Open in the REPL" target="_blank" href="https://mlochbaum.github.io/BQN/try.html#code=ISAyPTIgICMgUGFzc2VkCiEgMj0zICAjIEZhaWxlZA==">↗️</a><pre> <span class='Function'>!</span> <span class='Number'>2</span><span class='Function'>=</span><span class='Number'>2</span> <span class='Comment'># Passed </span>1 @@ -23,7 +23,7 @@ ERROR <span class='Bracket'>⟨</span><span class='Modifier2'>∘</span><span class='Separator'>,</span><span class='String'>"abc"</span><span class='Separator'>,</span><span class='Modifier'>˜</span><span class='Bracket'>⟩</span> <span class='Function'>!</span> <span class='String'>'0'</span> <span class='Comment'># Okay this is not a very helpful printout </span>ERROR </pre> -<h3 id="computing-the-error-message-on-demand">Computing the error message on demand</h3> +<h3 id="computing-the-error-message-on-demand"><a class="header" href="#computing-the-error-message-on-demand">Computing the error message on demand</a></h3> <p>Because the left argument to a function is always computed before the function is called, Assert <a href="../commentary/problems.html#assert-has-no-way-to-compute-the-error-message">doesn't let you</a> compute the error message only if there's an error. This might be a problem if the error message computation is slow or has side effects. There are a few ways to work around the issue:</p> <ul> <li>Handle errors with ordinary if-then logic (perhaps using <a href="control.html">control structures</a>). This is probably the best path for user-facing applications where displaying an error goes through the user interface.</li> |