[#MRDOCS_CHECK_OR_CONTINUE]
= MRDOCS_CHECK_OR_CONTINUE
:mrdocs:

Check a value and skip to the next loop iteration if it failed.

== Synopsis

Declared in `<mrdocs/Support/Error/Expected.hpp>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
#define MRDOCS_CHECK_OR_CONTINUE(var)

----

== Description

If the value failed, the macro runs `continue`. See `MRDOCS_TRY` for what counts as failed.

[,cpp]
----
// Node is the struct from the MRDOCS_CHECK_OR example.
int total = 0;
for (Node const* node : nodes)
{
    MRDOCS_CHECK_OR_CONTINUE(node);         // skip null pointers
    MRDOCS_CHECK_OR_CONTINUE(node->name);   // skip empty names
    MRDOCS_CHECK_OR_CONTINUE(node->n > 0);  // skip non-positive counts
    total += node->n;
}
----
The loop expands to roughly this (simplified: the real code calls `::mrdocs::detail::failed`):

[,cpp]
----
int total = 0;
for (Node const* node : nodes)
{
    // MRDOCS_CHECK_OR_CONTINUE(node);
    if (failed(node)) {         // !node, since node is a pointer
        continue;
    }

    // MRDOCS_CHECK_OR_CONTINUE(node->name);
    if (failed(node->name)) {   // node->name.empty(), a string
        continue;
    }

    // MRDOCS_CHECK_OR_CONTINUE(node->n > 0);
    if (failed(node->n > 0)) {  // the condition is false
        continue;
    }

    total += node->n;
}
----
The value is evaluated once, so a call expression like `MRDOCS_CHECK_OR_CONTINUE(isVisible(node))` is fine.

Things to keep in mind:

* Use it only inside a loop, and end it with a semicolon.
* The expansion is two statements. Put braces around it when it's the body of an `if` or `else`.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *var*
| The value to check.
|===


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