Errors

Vascula reports mistakes instead of rendering something wrong. Errors come from two phases:

• Compile errors mean the source is malformed. They are found as soon as the template is saved, before any data is involved.
• Render errors depend on the data: a name that is not allowed, a division by zero, a value that is too large.

Messages end with the position, (line L, col C), counting characters from 1, when one is known. In a child template the message starts with {% render %} "name": and the position is in the child's source.

#Compile errors

#{% x %} is never closed with {% endx %}

A block tag (if, unless, for, case, capture, form, comment) has no matching end tag. The position is where the block opens.

<ul>{% for item in settings.items %}<li>{{ item }}</li></ul>

{% for %} is never closed with {% endfor %} (line 1, col 5)

#unexpected {% endx %} with no opening tag

An end tag, else, elsif or when appears where no block is open, often because of a typo in the opening tag or an extra end tag.

{% if settings.a %}a{% endif %}{% endif %}

unexpected {% endif %} with no opening tag

#unknown tag "x"

The tag is not part of Vascula and the application did not declare a host tag with that name.

{% includes "footer" %}

unknown tag "includes"

#expected X, found Y

The tag or expression is malformed at that point. The message names what was expected and what was found.

{% assign total 5 %}

expected "=", found number "5" (line 1, col 17)

{{ product.title | }}

expected name, found "}}"

#unterminated ...

A string, {{, {% or {# is never closed. Vascula refuses rather than treating the rest of the file as part of it.

<p>{{ "unclosed }}</p>

unterminated string

#... is reserved

A name that cannot be bound was assigned, captured, used as a loop variable or passed to a child: settings, forloop, or a name the application reserved. Choose another name.

{% for forloop in (1..2) %}{% endfor %}

for variable "forloop" is reserved

#duplicate render argument

{% render "card", title: 1, title: 2 %}

duplicate render argument "title"

#{% render %} requires a literal template name

The name after render must be a quoted string.

{% render settings.name %}

requires a literal template name

#the {% raw %} block is not available

There is no way to print unescaped text from a template. See Output.

{% raw %}<b>{% endraw %}

the {% raw %} block is not available

#{% form %} errors

{% form %} needs a kind the application registered, and cannot set attributes the application controls (action, method, enctype). See Extending: forms.

#compile budget exceeded

The source is larger, or nests deeper, than the compilation limits allow. See Safety and limits.

#Render errors

#undeclared name "x"

The template read a name that is not a variable, not settings, not a global and not an allowed data root. Usually a typo, a missing assign, or data the template must ask the application to allow.

{{ customer.name }}

undeclared name "customer": it is not a variable or an allowed data root (line 1, col 4)

The Go error is a *vascula.UndeclaredNameError with the name; see Go API.

#unknown filter "x"

No built-in or application filter has that name.

{{ "x" | upcse }}

unknown filter "upcse"

#filter "x": ...

A filter rejected its input or arguments. The message says why.

{{ 10 | divided_by: 0 }}

filter "divided_by": divided_by: division by zero

{{ "tomorrow" | date: "%Y" }}

date: cannot parse "tomorrow" as a date

#filter "x" does not take a named argument "y"

Built-in filters accept only the named arguments they document (only default has one: allow_false). This usually means a filter's arguments swallowed the next render argument; put the filtered argument last. See Composition: arguments.

#cannot compare A and B with "op"

<, >, <= and >= need two numbers or two strings.

{% if settings.count > "3" %}{% endif %}

{"settings": {"count": 5}}

cannot compare number and string with ">"

#{% break %} outside a for loop

break and continue only work inside a loop. A child template cannot break its caller's loop.

{% break %}

{% break %} outside a for loop

#{% render %} ...

A child could not be rendered. The message continues with the reason: the application's resolver refused the name, the child failed (with its own message and position), or children nested more than 32 levels deep, which usually means a template renders itself.

#{% form %}: host token missing

The data root that holds the form token is missing or empty for this render. The application must supply it.

#render budget exceeded: ...

The render reached one of the rendering limits:

Reduce the data or the work; raise a limit only if a real template needs it.

#non-finite numbers are not supported

A value was infinite or not a number. Vascula refuses rather than printing NaN.