hcl/expr_call.go

47 lines
1.4 KiB
Go

package hcl
// ExprCall tests if the given expression is a function call and,
// if so, extracts the function name and the expressions that represent
// the arguments. If the given expression is not statically a function call,
// error diagnostics are returned.
//
// A particular Expression implementation can support this function by
// offering a method called ExprCall that takes no arguments and returns
// *StaticCall. This method should return nil if a static call cannot
// be extracted. Alternatively, an implementation can support
// UnwrapExpression to delegate handling of this function to a wrapped
// Expression object.
func ExprCall(expr Expression) (*StaticCall, Diagnostics) {
type exprCall interface {
ExprCall() *StaticCall
}
physExpr := UnwrapExpressionUntil(expr, func(expr Expression) bool {
_, supported := expr.(exprCall)
return supported
})
if exC, supported := physExpr.(exprCall); supported {
if call := exC.ExprCall(); call != nil {
return call, nil
}
}
return nil, Diagnostics{
&Diagnostic{
Severity: DiagError,
Summary: "Invalid expression",
Detail: "A static function call is required.",
Subject: expr.StartRange().Ptr(),
},
}
}
// StaticCall represents a function call that was extracted statically from
// an expression using ExprCall.
type StaticCall struct {
Name string
NameRange Range
Arguments []Expression
ArgsRange Range
}