Add fail templates

2020-07-02 19:59:01 +02:00
parent cd80913346
commit 8f27c5e552
3 changed files with 127 additions and 84 deletions
--- a/doc/op.html
+++ b/doc/op.html
@@ -102,7 +102,7 @@ function main() {
  <a class="reference reference-toplevel" href="#7" id="57">Types</a>
  <ul class="simple simple-toc-section">
      <li><a class="reference" href="#OP"
-    title="OP[T] = object of RootObj
+    title="OP[T] = object
  case isOk*: bool
  of true:
      val*: T
@@ -119,13 +119,21 @@ function main() {
    title="ok[T](val: T): OP[T]"><wbr />ok<span class="attachedType">OP</span></a></li>
  <li><a class="reference" href="#fail%2COP%2Cstring"
    title="fail(op: OP; msg: string): OP"><wbr />fail<span class="attachedType">OP</span></a></li>
-  <li><a class="reference" href="#fail%2Cstring"
-    title="fail[T](msg: string): OP[T]"><wbr />fail<span class="attachedType">OP</span></a></li>
  <li><a class="reference" href="#fail%2Ctypedesc%2Cstring"
    title="fail(T: typedesc; msg: string): OP[T]"><wbr />fail<span class="attachedType">OP</span></a></li>

  </ul>
 </li>
+<li>
+  <a class="reference reference-toplevel" href="#18" id="68">Templates</a>
+  <ul class="simple simple-toc-section">
+      <li><a class="reference" href="#fail.t%2C%2Cstring"
+    title="fail[T; ](O: type OP[T]; msg: string): O:type"><wbr />fail<span class="attachedType">OP</span></a></li>
+  <li><a class="reference" href="#fail.t%2Cstatic%5Bstring%5D"
+    title="fail(msg: static[string]): auto"><wbr />fail<span class="attachedType"></span></a></li>
+
+  </ul>
+</li>

 </ul>

@@ -142,7 +150,7 @@ function main() {
 <h1><a class="toc-backref" id="basic-usage" href="#basic-usage">Basic Usage</a></h1><pre class="listing"><span class="Keyword">proc</span> <span class="Identifier">divide</span><span class="Punctuation">(</span><span class="Identifier">a</span><span class="Punctuation">,</span> <span class="Identifier">b</span><span class="Punctuation">:</span> <span class="Identifier">int</span><span class="Punctuation">)</span><span class="Punctuation">:</span> <span class="Identifier">OP</span><span class="Punctuation">[</span><span class="Identifier">float</span><span class="Punctuation">]</span> <span class="Operator">=</span>
  <span class="Comment">## This could fail</span>
  <span class="Keyword">if</span> <span class="Identifier">b</span> <span class="Operator">==</span> <span class="DecNumber">0</span><span class="Punctuation">:</span>
-    <span class="Keyword">return</span> <span class="Identifier">fail</span><span class="Punctuation">(</span><span class="Identifier">float</span><span class="Punctuation">,</span> <span class="StringLit">&quot;Cannot divide by zero!&quot;</span><span class="Punctuation">)</span>
+    <span class="Keyword">return</span> <span class="Identifier">fail</span> <span class="StringLit">&quot;Cannot divide by zero!&quot;</span>
  <span class="Keyword">else</span><span class="Punctuation">:</span>
    <span class="Keyword">return</span> <span class="Identifier">ok</span> <span class="Identifier">a</span> <span class="Operator">/</span> <span class="Identifier">b</span>   <span class="Comment"># Wrap the result</span>

@@ -153,7 +161,7 @@ function main() {
 <h1><a class="toc-backref" href="#7">Types</a></h1>
 <dl class="item">
 <a id="OP"></a>
-<dt><pre><a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span> <span class="Other">=</span> <span class="Keyword">object</span> <span class="Keyword">of</span> <span class="Identifier">RootObj</span>
+<dt><pre><a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span> <span class="Other">=</span> <span class="Keyword">object</span>
  <span class="Keyword">case</span> <span class="Identifier">isOk</span><span class="Operator">*</span><span class="Other">:</span> <span class="Identifier">bool</span>
  <span class="Keyword">of</span> <span class="Identifier">true</span><span class="Other">:</span>
      <span class="Identifier">val</span><span class="Operator">*</span><span class="Other">:</span> <span class="Identifier">T</span>
@@ -164,7 +172,9 @@ function main() {
  </pre></dt>
 <dd>

-Object to wrap the result of an operation<ul class="simple"><li><tt class="docutils literal"><span class="pre">isOk</span></tt>: Indicates if the operation was successful</li>
+<p>Object to wrap the result of an operation.</p>
+<p>The type is discriminated by the <tt class="docutils literal"><span class="pre">isOK</span></tt> bool. So it is an compiler error to try to access the value without checking if the operation was successful.</p>
+<ul class="simple"><li><tt class="docutils literal"><span class="pre">isOk</span></tt>: Indicates if the operation was successful</li>
 <li><tt class="docutils literal"><span class="pre">val</span></tt>: If successful, this will hold the real result value</li>
 <li><tt class="docutils literal"><span class="pre">error</span></tt>: Otherwise this will hold an error message</li>
 </ul>
@@ -177,14 +187,14 @@ Object to wrap the result of an operation<ul class="simple"><li><tt class="docut
 <h1><a class="toc-backref" href="#12">Procs</a></h1>
 <dl class="item">
 <a id="ok,T"></a>
-<dt><pre><span class="Keyword">proc</span> <a href="#ok%2CT"><span class="Identifier">ok</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span><span class="Other">(</span><span class="Identifier">val</span><span class="Other">:</span> <span class="Identifier">T</span><span class="Other">)</span><span class="Other">:</span> <a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span></pre></dt>
+<dt><pre><span class="Keyword">proc</span> <a href="#ok%2CT"><span class="Identifier">ok</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span><span class="Other">(</span><span class="Identifier">val</span><span class="Other">:</span> <span class="Identifier">T</span><span class="Other">)</span><span class="Other">:</span> <a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span> <span><span class="Other">{</span><span class="Other pragmadots">...</span><span class="Other">}</span></span><span class="pragmawrap"><span class="Other">{.</span><span class="pragma"><span class="Identifier">inline</span></span><span class="Other">.}</span></span></pre></dt>
 <dd>

 Wraps the given value in a successful operation result.

 </dd>
 <a id="fail,OP,string"></a>
-<dt><pre><span class="Keyword">proc</span> <a href="#fail%2COP%2Cstring"><span class="Identifier">fail</span></a><span class="Other">(</span><span class="Identifier">op</span><span class="Other">:</span> <a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">;</span> <span class="Identifier">msg</span><span class="Other">:</span> <span class="Identifier">string</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">OP</span></pre></dt>
+<dt><pre><span class="Keyword">proc</span> <a href="#fail%2COP%2Cstring"><span class="Identifier">fail</span></a><span class="Other">(</span><span class="Identifier">op</span><span class="Other">:</span> <a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">;</span> <span class="Identifier">msg</span><span class="Other">:</span> <span class="Identifier">string</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">OP</span> <span><span class="Other">{</span><span class="Other pragmadots">...</span><span class="Other">}</span></span><span class="pragmawrap"><span class="Other">{.</span><span class="pragma"><span class="Identifier">inline</span></span><span class="Other">.}</span></span></pre></dt>
 <dd>

 Will create a new operation result with the given error message. The type for the operation result is taken from the <tt class="docutils literal"><span class="pre">op</span></tt> argument.
@@ -197,26 +207,35 @@ Will create a new operation result with the given error message. The type for th
 <span class="Identifier">assert</span> <span class="Identifier">data</span><span class="Other">.</span><span class="Identifier">error</span> <span class="Operator">==</span> <span class="StringLit">&quot;Not implemented!&quot;</span></pre>

 </dd>
-<a id="fail,string"></a>
-<dt><pre><span class="Keyword">proc</span> <a href="#fail%2Cstring"><span class="Identifier">fail</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span><span class="Other">(</span><span class="Identifier">msg</span><span class="Other">:</span> <span class="Identifier">string</span><span class="Other">)</span><span class="Other">:</span> <a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span></pre></dt>
+<a id="fail,typedesc,string"></a>
+<dt><pre><span class="Keyword">proc</span> <a href="#fail%2Ctypedesc%2Cstring"><span class="Identifier">fail</span></a><span class="Other">(</span><span class="Identifier">T</span><span class="Other">:</span> <span class="Identifier">typedesc</span><span class="Other">;</span> <span class="Identifier">msg</span><span class="Other">:</span> <span class="Identifier">string</span><span class="Other">)</span><span class="Other">:</span> <a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span> <span><span class="Other">{</span><span class="Other pragmadots">...</span><span class="Other">}</span></span><span class="pragmawrap"><span class="Other">{.</span><span class="pragma"><span class="Identifier">inline</span></span><span class="Other">.}</span></span></pre></dt>
 <dd>

 <p>Will create a new operation result with the given error message. The type for the operation result is given explicitly.</p>
 <p><strong>See Also:</strong></p>
 <ul class="simple"><li><a class="reference external" href="#fail,OP,string">fail proc</a></li>
+<li><a class="reference external" href="#fail.t,static[string]">fail template</a></li>
 </ul>

-<p><strong class="examples_text">Examples:</strong></p>
-<pre class="listing"><span class="Keyword">let</span> <span class="Identifier">res</span> <span class="Other">=</span> <span class="Identifier">fail</span><span class="Other">[</span><span class="Identifier">seq</span><span class="Other">[</span><span class="Identifier">float</span><span class="Other">]</span><span class="Other">]</span> <span class="StringLit">&quot;Something is wrong!&quot;</span>
-<span class="Identifier">assert</span> <span class="Identifier">res</span><span class="Other">.</span><span class="Identifier">isOk</span> <span class="Operator">==</span> <span class="Identifier">false</span>
-<span class="Identifier">assert</span> <span class="Identifier">res</span><span class="Other">.</span><span class="Identifier">error</span> <span class="Operator">==</span> <span class="StringLit">&quot;Something is wrong!&quot;</span></pre>

 </dd>
-<a id="fail,typedesc,string"></a>
-<dt><pre><span class="Keyword">proc</span> <a href="#fail%2Ctypedesc%2Cstring"><span class="Identifier">fail</span></a><span class="Other">(</span><span class="Identifier">T</span><span class="Other">:</span> <span class="Identifier">typedesc</span><span class="Other">;</span> <span class="Identifier">msg</span><span class="Other">:</span> <span class="Identifier">string</span><span class="Other">)</span><span class="Other">:</span> <a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span></pre></dt>
+
+</dl></div>
+<div class="section" id="18">
+<h1><a class="toc-backref" href="#18">Templates</a></h1>
+<dl class="item">
+<a id="fail.t,,string"></a>
+<dt><pre><span class="Keyword">template</span> <a href="#fail.t%2C%2Cstring"><span class="Identifier">fail</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">;</span> <span class="Other">]</span><span class="Other">(</span><span class="Identifier">O</span><span class="Other">:</span> <span class="Keyword">type</span> <a href="op.html#OP"><span class="Identifier">OP</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span><span class="Other">;</span> <span class="Identifier">msg</span><span class="Other">:</span> <span class="Identifier">string</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">O:type</span></pre></dt>
 <dd>

-Alias for <a class="reference external" href="#fail,string">fail[T](string)</a>
+
+
+</dd>
+<a id="fail.t,static[string]"></a>
+<dt><pre><span class="Keyword">template</span> <a href="#fail.t%2Cstatic%5Bstring%5D"><span class="Identifier">fail</span></a><span class="Other">(</span><span class="Identifier">msg</span><span class="Other">:</span> <span class="Identifier">static</span><span class="Other">[</span><span class="Identifier">string</span><span class="Other">]</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">auto</span></pre></dt>
+<dd>
+
+

 </dd>

@@ -229,7 +248,7 @@ Alias for <a class="reference external" href="#fail,string">fail[T](string)</a>
      <div class="twelve-columns footer">
        <span class="nim-sprite"></span>
        <br/>
-        <small style="color: var(--hint);">Made with Nim. Generated: 2020-07-02 16:37:38 UTC</small>
+        <small style="color: var(--hint);">Made with Nim. Generated: 2020-07-02 17:57:25 UTC</small>
      </div>
    </div>
  </div>
--- a/src/op.nim
+++ b/src/op.nim
@@ -17,7 +17,7 @@
 ##  proc divide(a, b: int): OP[float] =
 ##    ## This could fail
 ##    if b == 0:
-##      return fail(float, "Cannot divide by zero!")
+##      return fail "Cannot divide by zero!"
 ##    else:
 ##      return ok a / b   # Wrap the result
 ##
@@ -26,8 +26,12 @@
 ##  assert r.error == "Cannot divide by zero!"

 type
-  OP*[T] = object of RootObj
-    ## Object to wrap the result of an operation
+  OP*[T] = object
+    ## Object to wrap the result of an operation.
+    ##
+    ## The type is discriminated by the `isOK` bool.
+    ## So it is an compiler error to try to access the value without checking
+    ## if the operation was successful.
    ##
    ## - `isOk`: Indicates if the operation was successful
    ## - `val`: If successful, this will hold the real result value
@@ -38,11 +42,11 @@ type
    of false:
      error*: string

-proc ok*[T](val: T): OP[T] =
+proc ok*[T](val: T): OP[T] {.inline.} =
  ## Wraps the given value in a successful operation result.
  OP[T](isOK: true, val: val)

-proc fail*(op: OP, msg: string): OP =
+proc fail*(op: OP, msg: string): OP {.inline.} =
  ## Will create a new operation result with the given error message.
  ## The type for the operation result is taken from the `op` argument.
  runnableExamples:
@@ -54,20 +58,17 @@ proc fail*(op: OP, msg: string): OP =
    assert data.error == "Not implemented!"
  OP(isOK: false, error: msg)

-proc fail*[T](msg: string): OP[T] =
+proc fail*(T: typedesc, msg: string): OP[T] {.inline.} =
  ## Will create a new operation result with the given error message.
  ## The type for the operation result is given explicitly.
  ##
  ## **See Also:**
-  ## - `fail proc
-  ##   <#fail,OP,string>`_
-  runnableExamples:
-    let res = fail[seq[float]] "Something is wrong!"
-    assert res.isOk == false
-    assert res.error == "Something is wrong!"
+  ## - `fail proc<#fail,OP,string>`_
+  ## - `fail template<#fail.t,static[string]>`_
  OP[T](isOK: false, error: msg)

-proc fail*(T: typedesc, msg: string): OP[T] =
-  ## Alias for `fail[T](string)<#fail,string>`_
-  fail[T] msg
+template fail*[T](O: type OP[T], msg: string): O = O(isOK: false, error: msg)
+
+template fail*(msg: static[string]): auto = fail(typeof(result), msg)
+

--- a/tests/tests.nim
+++ b/tests/tests.nim
@@ -3,12 +3,13 @@
 import unittest
 import op

+suite "Basic tests":
  test "Check OK":
    let test = ok 1
    check test.isOk == true

  test "Check fail":
-  let test = op.fail[int] "no data here"
+    let test = fail(void, "no data here")
    check test.isOk == false

  test "Check proc results":
@@ -29,7 +30,7 @@ test "Check failing result proc":

  test "Check failing typedesc proc ":
    proc someProc(): OP[int] =
-    fail(int, "Not implemented!")
+      op.fail(int, "Not implemented!")

    let data = someProc()
    assert data.isOk == false
@@ -37,7 +38,7 @@ test "Check failing typedesc proc ":

  test "Check failing type param proc ":
    proc someProc(): OP[int] =
-    op.fail[int]("Not implemented!")
+      fail(int, "Not implemented!")

    let data = someProc()
    assert data.isOk == false
@@ -66,3 +67,25 @@ test "Check divider proc":
    let r = divide(a, b)
    check r.isOk == false
    check r.error == "Cannot divide by zero!"
+
+  test "Check implicit fail type":
+    proc divide(a, b: int): OP[float] =
+      if b == 0:
+        return fail "Cannot divide by zero!"
+      else:
+        return ok a / b
+
+    let r = divide(1, 0)
+    check r.isOk == false
+    check r.error == "Cannot divide by zero!"
+
+  test "Check type of impolicit fail":
+      proc divide(a, b: int): OP[float] =
+        if b == 0:
+          return fail "Cannot divide by zero!"
+        else:
+          return ok a / b
+
+      let r = divide(1, 0)
+      check r.isOk == false
+      check r.error == "Cannot divide by zero!"