1<!-- Generated with Stardoc: http://skydoc.bazel.build --> 2 3Starlark module for working with partial function objects. 4 5Partial function objects allow some parameters are bound before the call. 6 7Similar to https://docs.python.org/3/library/functools.html#functools.partial. 8 9<a id="partial.call"></a> 10 11## partial.call 12 13<pre> 14partial.call(<a href="#partial.call-partial">partial</a>, <a href="#partial.call-args">args</a>, <a href="#partial.call-kwargs">kwargs</a>) 15</pre> 16 17Calls a partial created using `make`. 18 19**PARAMETERS** 20 21 22| Name | Description | Default Value | 23| :------------- | :------------- | :------------- | 24| <a id="partial.call-partial"></a>partial | The partial to be called. | none | 25| <a id="partial.call-args"></a>args | Additional positional arguments to be appended to the ones given to make. | none | 26| <a id="partial.call-kwargs"></a>kwargs | Additional keyword arguments to augment and override the ones given to make. | none | 27 28**RETURNS** 29 30Whatever the function in the partial returns. 31 32 33<a id="partial.is_instance"></a> 34 35## partial.is_instance 36 37<pre> 38partial.is_instance(<a href="#partial.is_instance-v">v</a>) 39</pre> 40 41Returns True if v is a partial created using `make`. 42 43**PARAMETERS** 44 45 46| Name | Description | Default Value | 47| :------------- | :------------- | :------------- | 48| <a id="partial.is_instance-v"></a>v | The value to check. | none | 49 50**RETURNS** 51 52True if v was created by `make`, False otherwise. 53 54 55<a id="partial.make"></a> 56 57## partial.make 58 59<pre> 60partial.make(<a href="#partial.make-func">func</a>, <a href="#partial.make-args">args</a>, <a href="#partial.make-kwargs">kwargs</a>) 61</pre> 62 63Creates a partial that can be called using `call`. 64 65A partial can have args assigned to it at the make site, and can have args 66passed to it at the call sites. 67 68A partial 'function' can be defined with positional args and kwargs: 69 70 # function with no args 71 ``` 72 def function1(): 73 ... 74 ``` 75 76 # function with 2 args 77 ``` 78 def function2(arg1, arg2): 79 ... 80 ``` 81 82 # function with 2 args and keyword args 83 ``` 84 def function3(arg1, arg2, x, y): 85 ... 86 ``` 87 88The positional args passed to the function are the args passed into make 89followed by any additional positional args given to call. The below example 90illustrates a function with two positional arguments where one is supplied by 91make and the other by call: 92 93 # function demonstrating 1 arg at make site, and 1 arg at call site 94 ``` 95 def _foo(make_arg1, func_arg1): 96 print(make_arg1 + " " + func_arg1 + "!") 97 ``` 98 99For example: 100 101 ``` 102 hi_func = partial.make(_foo, "Hello") 103 bye_func = partial.make(_foo, "Goodbye") 104 partial.call(hi_func, "Jennifer") 105 partial.call(hi_func, "Dave") 106 partial.call(bye_func, "Jennifer") 107 partial.call(bye_func, "Dave") 108 ``` 109 110prints: 111 112 ``` 113 "Hello, Jennifer!" 114 "Hello, Dave!" 115 "Goodbye, Jennifer!" 116 "Goodbye, Dave!" 117 ``` 118 119The keyword args given to the function are the kwargs passed into make 120unioned with the keyword args given to call. In case of a conflict, the 121keyword args given to call take precedence. This allows you to set a default 122value for keyword arguments and override it at the call site. 123 124Example with a make site arg, a call site arg, a make site kwarg and a 125call site kwarg: 126 127 ``` 128 def _foo(make_arg1, call_arg1, make_location, call_location): 129 print(make_arg1 + " is from " + make_location + " and " + 130 call_arg1 + " is from " + call_location + "!") 131 132 func = partial.make(_foo, "Ben", make_location="Hollywood") 133 partial.call(func, "Jennifer", call_location="Denver") 134 ``` 135 136Prints "Ben is from Hollywood and Jennifer is from Denver!". 137 138 ``` 139 partial.call(func, "Jennifer", make_location="LA", call_location="Denver") 140 ``` 141 142Prints "Ben is from LA and Jennifer is from Denver!". 143 144Note that keyword args may not overlap with positional args, regardless of 145whether they are given during the make or call step. For instance, you can't 146do: 147 148``` 149def foo(x): 150 pass 151 152func = partial.make(foo, 1) 153partial.call(func, x=2) 154``` 155 156 157**PARAMETERS** 158 159 160| Name | Description | Default Value | 161| :------------- | :------------- | :------------- | 162| <a id="partial.make-func"></a>func | The function to be called. | none | 163| <a id="partial.make-args"></a>args | Positional arguments to be passed to function. | none | 164| <a id="partial.make-kwargs"></a>kwargs | Keyword arguments to be passed to function. Note that these can be overridden at the call sites. | none | 165 166**RETURNS** 167 168A new `partial` that can be called using `call` 169 170 171