public abstract class AstPrimitive<T extends AstPrimitive<T>> extends AstRoot<T>
| Constructor and Description |
|---|
AstPrimitive() |
| Modifier and Type | Method and Description |
|---|---|
abstract Val |
apply(Env env,
Env.StackHelp stk,
AstRoot[] asts)
Primary method to invoke this function, passing all the parameters
as the `asts` list.
|
abstract java.lang.String[] |
args()
List of argument names.
|
java.lang.String |
description()
Return the detailed description (help) for what this language construct
does or how it is supposed to be used.
|
java.lang.String |
example()
Return an example of how this Ast construct ought to be used.
|
ValFun |
exec(Env env)
"Execute" this AST expression, and return the result.
|
abstract int |
nargs()
Number of function's arguments + 1.
|
asBytes, clone, copyOver, frozenType, read, readExternal, readJSON, reloadFromBytes, toJsonString, write, writeExternal, writeJSONpublic abstract int nargs()
public abstract java.lang.String[] args()
public abstract Val apply(Env env, Env.StackHelp stk, AstRoot[] asts)
Primary method to invoke this function, passing all the parameters as the `asts` list.
env - Current execution environment. Variables are looked up here.stk - TODO need clarificationasts - List of AstRoot expressions that are arguments to the
function. First element in this list is the function itself.public ValFun exec(Env env)
AstRoot"Execute" this AST expression, and return the result. For different ASTs this may have different interpretation. For example, consider this Rapids expression:
(mean frame True False)
It will be parsed into the following structure:
AstExec() instance with
_asts = [AstMean() singleton instance,
new AstId(frame),
AstConst.TRUE,
AstConst.FALSE]
Execution of AstExec will execute its first argument, _asts[0],
verify that it produces a function (ValFun), then call
apply(Env, Env.StackHelp, AstRoot[]) on that function
passing down the list of _asts arguments.
The AstMean class will in turn execute all its arguments,
where execution of AstId fetches the referred symbol from the
environment, and execution of AstConst returns the value of that
constant.
Certain other functions may choose not to evaluate all their arguments (for example boolean expressions providing short-circuit evaluation).
exec in class AstRoot<T extends AstPrimitive<T>>public java.lang.String example()
AstRootReturn an example of how this Ast construct ought to be used. This
method is used to build documentation for the Rapids language. It is
different from AstRoot.str(), in particular it must provide a valid
example even in a static context. For example, an AstStr may
return "Hello, world!" as an example. At the same time,
for different AstPrimitives this method should generally provide
a typical example of how that function is to be used.
Return null to indicate that the object should not be
included in the documentation.
example in class AstRoot<T extends AstPrimitive<T>>public java.lang.String description()
AstRootReturn the detailed description (help) for what this language construct
does or how it is supposed to be used. This method is used in conjunction
with AstRoot.example() to build the documentation of the Rapids
language.
If you need to include any formatting, then please use Markup language. Although it is up to the client to support it, Markup is one of the simplest and easiest alternatives.
Return null to indicate that the object should not be
included in the documentation.
description in class AstRoot<T extends AstPrimitive<T>>