mildew.binder source code

1 /**
2  * Contains functions to mixin to simplify code reuse. For these to work, the parameters of a native function
3  * must be called context, thisObj, args, and nfe.
4  */
5 module mildew.binder;
6 
7 import std.format: format;
8 import std.conv: to;
9 
10 /**
11  * Check for a minimum number of arguments. This must be used if using TO_ARG
12  */
13 string CHECK_MINIMUM_ARGS(int num)()
14 {
15     return format(q{
16         if(args.length < %1$s)
17         {
18             nfe = NativeFunctionError.WRONG_NUMBER_OF_ARGS;
19             return ScriptAny.UNDEFINED;
20         }
21     }, num.to!string);
22 }
23 
24 /**
25  * Shorthand for validating a this object as a native type
26  */
27 string CHECK_THIS_NATIVE_OBJECT(string varName, alias dclass)()
28 {
29     return format(q{
30         auto %1$s = thisObj.toNativeObject!%2$s;
31         if(%1$s is null)
32         {
33             nfe = NativeFunctionError.WRONG_TYPE_OF_ARG;
34             return ScriptAny.UNDEFINED;
35         }
36     }, varName, dclass.stringof);
37 }
38 
39 /**
40  * Uses .init value of a variable if argument doesn't exist. Arguments length MUST be checked first
41  */
42 string TO_ARG(string varName, int index, alias type)()
43 {
44     return format(q{
45         auto %1$s = args[%2$s].toValue!%3$s;
46     }, varName, index.to!string, type.stringof);
47 }
48 
49 /**
50  * Get an optional argument and default value
51  */
52 string TO_ARG_OPT(string varName, int index, alias defaultValue, alias type)()
53 {
54     return format(q{
55         auto %1$s = %3$s;
56         if(%2$s < args.length)
57         {
58             %1$s = args[%2$s].toValue!%4$s;
59         }
60     }, varName, index.to!string, defaultValue.stringof, type.stringof);
61 }
62 
63 /**
64  * Shorthand for extracting an argument without validating its type
65  */
66 string TO_ARG_CHECK_INDEX(string varName, int index, alias type)()
67 {   
68     return format(q{
69         if(args.length < %2$s + 1)
70         {
71             nfe = NativeFunctionError.WRONG_NUMBER_OF_ARGS;
72             return ScriptAny.UNDEFINED;
73         }
74         auto %1$s = args[%2$s].toValue!%3$s;
75     }, varName, index.to!string, type.stringof);
76 }
77