I just wonder if there is any simple and convinient way of handling possible null values in intermediate object in an expresssion:
request.service.contact.phone
I tried to surround it with (), but it did not work, when for example contact was null:
InvalidReferenceException: The following has evaluated to null or missing:
(request.service.contact.phone)!
I tried to escape each object, but FM thought that following expression part is builtin
ParseException: Unknown built-in variable: phone
request.service!.contact!.phone!
I will need to add conditionals but I do not like multiple if nesting. Is there something smarter?
Related
Is there a way to do the following in a html/template?
{{template "mytemplate" struct{Foo1, Foo2 string}{"Bar1", "Bar2"}}}
Actually in the template, like above. Not via a function registered in FuncMap which returns the struct.
I tried it, but Parse panics, see Playground. Maybe just the syntax is wrong?
As noted by others, it's not possible. Templates are parsed at runtime, without the help of the Go compiler. So allowing arbitrary Go syntax would not be feasible (although note that it wouldn't be impossible, as the standard lib contains all the tools to parse Go source text, see packages "prefixed" with go/ in the standard lib). By design philosophy, complex logic should be outside of templates.
Back to your example:
struct{Foo1, Foo2 string}{"Bar1", "Bar2"}
This is a struct composite literal and it is not supported in templates, neither when invoking another template nor at other places.
Invoking another template with a custom "argument" has the following syntax (quoting from text/template: Actions):
{{template "name" pipeline}}
The template with the specified name is executed with dot set
to the value of the pipeline.
TL;DR; A pipeline may be a constant, an expression denoting a field or method of some value (where the method will be called and its return value will be used), it may be a call to some "template-builtin" function or a custom registered function, or a value in a map.
Where Pipeline is:
A pipeline is a possibly chained sequence of "commands". A command is a simple value (argument) or a function or method call, possibly with multiple arguments:
Argument
The result is the value of evaluating the argument.
.Method [Argument...]
The method can be alone or the last element of a chain but,
unlike methods in the middle of a chain, it can take arguments.
The result is the value of calling the method with the
arguments:
dot.Method(Argument1, etc.)
functionName [Argument...]
The result is the value of calling the function associated
with the name:
function(Argument1, etc.)
Functions and function names are described below.
And an Argument is:
An argument is a simple value, denoted by one of the following.
- A boolean, string, character, integer, floating-point, imaginary
or complex constant in Go syntax. These behave like Go's untyped
constants. Note that, as in Go, whether a large integer constant
overflows when assigned or passed to a function can depend on whether
the host machine's ints are 32 or 64 bits.
- The keyword nil, representing an untyped Go nil.
- The character '.' (period):
.
The result is the value of dot.
- A variable name, which is a (possibly empty) alphanumeric string
preceded by a dollar sign, such as
$piOver2
or
$
The result is the value of the variable.
Variables are described below.
- The name of a field of the data, which must be a struct, preceded
by a period, such as
.Field
The result is the value of the field. Field invocations may be
chained:
.Field1.Field2
Fields can also be evaluated on variables, including chaining:
$x.Field1.Field2
- The name of a key of the data, which must be a map, preceded
by a period, such as
.Key
The result is the map element value indexed by the key.
Key invocations may be chained and combined with fields to any
depth:
.Field1.Key1.Field2.Key2
Although the key must be an alphanumeric identifier, unlike with
field names they do not need to start with an upper case letter.
Keys can also be evaluated on variables, including chaining:
$x.key1.key2
- The name of a niladic method of the data, preceded by a period,
such as
.Method
The result is the value of invoking the method with dot as the
receiver, dot.Method(). Such a method must have one return value (of
any type) or two return values, the second of which is an error.
If it has two and the returned error is non-nil, execution terminates
and an error is returned to the caller as the value of Execute.
Method invocations may be chained and combined with fields and keys
to any depth:
.Field1.Key1.Method1.Field2.Key2.Method2
Methods can also be evaluated on variables, including chaining:
$x.Method1.Field
- The name of a niladic function, such as
fun
The result is the value of invoking the function, fun(). The return
types and values behave as in methods. Functions and function
names are described below.
- A parenthesized instance of one the above, for grouping. The result
may be accessed by a field or map key invocation.
print (.F1 arg1) (.F2 arg2)
(.StructValuedMethod "arg").Field
The proper solution would be to register a custom function that constructs the value you want to pass to the template invocation, as you can see in this related / possible duplicate: Golang pass multiple values from template to template?
Another, half solution could be to use the builtin print or printf functions to concatenate the values you want to pass, but that would require to split in the other template.
As mentioned by #icza, this is not possible.
However, you might want to provide a generic dict function to templates to allow to build a map[string]interface{} from a list of arguments. This is explained in this other answer: https://stackoverflow.com/a/18276968/328115
I'm trying to run a FOR loop on robot framework depending of the status of another variable.
${STATUS1}= Run Keyword And Return Status Should Be Equal As Strings ${CELLVALUE} ${EXPECTEDVALUE}
\ ${COUNT}= Set Variable If '${STATUS1}' == 'True' ${COUNT}+1
\ ... '${STATUS1}' == 'False' ${COUNT}+0
But all I get is '''0'+0'+0'+1 or similar, even if I use Run keyword If and Evaluate instead of set var, I tried to convert to integer but nothing happens and I cannot convert it to integer or number. Any suggestions? thanks in advance!
It looks like you're simply wanting to increment ${COUNT} if ${CELLVALUE} equals ${EXPECTEDVALUE}. That can be done pretty easily with Set Variable if
If you know that ${CELLVALUE} and ${EXPECTEDVALUE} are of the same internal type (eg: strings or ints), and you're using robot framework 2.9 or greater, you can write it like this:
${COUNT}= Set variable if $CELLVALUE == $EXPECTEDVALUE
... ${COUNT+1} ${COUNT}
This assumes that ${COUNT} is initialized to an integer value, which you can do by assigning it the value ${0}
If you don't know the type, can't guarantee the type, or are using an older version of robot, you can use triple-quoted strings to coerce the values to strings:
${COUNT}= Set variable if '''${CELLVALUE}''' == '''${EXPECTEDVALUE}'''
... ${COUNT+1} ${COUNT}
Of course, you could use Run Keyword and Return Status like in your example, and then compare the status. That seems like an unnecessary extra step, but it might make sense in your actual test.
The point being, you can use Set variable if and extended variable syntax to solve this problem.
Note 1: With Set variable if, two values are provided. The first value is assigned if the expression is true, the second one is assigned if the value is false. The second value is the original variable, meaning it won't be changed. If you don't provide the second value, the variable will be set to None.
Note 2: Putting an expression inside curly braces (eg: ${COUNT+1} is documented in rule 4 of extended variable syntax.
Note 3: Starting with robot framework 2.9, variables are available in the evaluation namespace with the simplified syntax $varname. So, the robot variable ${CELLVALUE} can be used in python expressions as $CELLVALUE. This is documented in the section Evaluating Expressions in the BuiltIn library documentation.
I was working on a simple task yesterday, just needed to sum the values in a handful of dropdown menus to display in a textbox via Javascript. Unexpectedly, it was just building a string so instead of giving me the value 4 it gave me "1111". I understand what was happening; but I don't understand how.
With a loosely typed language like Javascript or PHP, how does the computer "know" what type to treat something as? If I just type everything as a var, how does it differentiate a string from an int from an object?
What the + operator will do in Javascript is determined at runtime, when both actual arguments (and their types) are known.
If the runtime sees that one of the arguments is a string, it will do string concatenation. Otherwise it will do numeric addition (if necessary coercing the arguments into numbers).
This logic is coded into the implementation of the + operator (or any other function like it). If you looked at it, you would see if typeof(a) === 'string' statements (or something very similar) in there.
If I just type everything as a var
Well, you don't type it at all. The variable has no type, but any actual value that ends up in that variable has a type, and code can inspect that.
I'm getting (fairly reguarly) an "Error 16: Expression too complex" runtime error on a simple assigment to a property from a class.
public property PropertyName() as double
PropertyName = mvarPropertyName
end property
The debug window points to the crash being on the assignment line in the above code.
Some inital reading here and elsewhere suggested that it was related to the line calling the property. However, that now looks like this:
variableName = ObjectName.PropertyName
And all arithmetic is done with variableName.
Even more oddly, if I just hit debug, then resume/F5 immediatley, everything is fine.
Trying to use the error handling code to do this doesn't seem to have worked however.
Any ideas what is causing this error?
Stop using Not (Not MyArray) to test for uninitialized arrays. This uses a bug in the compiler that has a known side effect of destabilizing the run-time leading to "Expression too complex" on random places.
VB6 - Returning/Detecting Empty Arrays is fairly complete thread on different ways to test for empty and uninitialized arrays.
A string expression is too complicated. Strings not assigned to variables (such as those returned by functions) are assigned to temporary locations during string expression evaluation. Having a large number of these strings can cause this error. Try assigning these strings to variables and use the variables in the expression instead.
I am trying to test whether a string can be converted into a number in FreeMarker. For example, "123" and "3.14" can be converted, but "foo" can't. I know that I can test for this by using the number method on the string (e.g. "123"?number) and seeing whether it produces an error, but I am looking for a way to test for this without causing an error.
I tried ?matches("^\d+$"), and it works fine for integers, but I am looking for something that works on all numbers.
I can probably do it using a more sophisticated regex, but I am wondering if there is a simpler way.
The simpler way is to not do it in FreeMarker :-) This sounds like something controller (or method on model) should be doing rather than view template. That said, you have a few options:
Use ?number built-in within <#attempt> / <#recover> block.
Write a method in one of your model objects to check whether your string into a number and invoke it from the template.
Write a custom directive to do this for you.