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Src/external_dependencies/openmpt-trunk/include/premake/website/docs/externalrule.md

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+Provides a way to reference rules that were created manually, outside of Premake.
+
+```lua
+externalrule ("name")
+```
+
+The `externalrule()` function behaves just like [rule()](rule.md), except that it does not output any rule file(s) at project generation time. You may use it to reference a hand-written or pre-existing rule file.
+
+
+### Parameters ###
+
+`name` is name of the rule. As with [rule()](rule.md), it is used as the default file name, and may be overridden with [filename](filename.md) and [location](location.md).
+
+
+### Availability ###
+
+Premake 5.0 or later; currently Visual Studio only.
+
+
+## Examples ##
+
+```lua
+externalrule "luac"
+  location "../rules"  -- optional; if the file lives somewhere other than the script folder
+  filename "lua-to-c"  -- optional; if the file has a name different than the rule
+  fileextension ".lua" -- required; which files should be associated with the rule?
+
+  propertydefinition {
+    name = "StripDebugInfo",
+    kind = "boolean",
+  }
+```
+
+`fileextension()` is required; this tells Premake which files in the project should be associated with the rule. `location()` is optional, and only needs to be specified if the rule files lives somewhere other than the folder containing the script. Likewise, `filename()` only needs to be specified if the rule file has a different name than the rule itself.
+
+You do not need to specify all of the properties in the rule, only those you intend to set from your project scripts.
+
+The external rule file does not need to exist at the time the workspace is generated.