6c4344623b
The main HCL package is more visible this way, and so it's easier than having to pick it out from dozens of other package directories.
43 lines
2.0 KiB
Go
43 lines
2.0 KiB
Go
package userfunc
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import (
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"github.com/hashicorp/hcl/v2"
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"github.com/zclconf/go-cty/cty/function"
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)
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// A ContextFunc is a callback used to produce the base EvalContext for
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// running a particular set of functions.
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//
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// This is a function rather than an EvalContext directly to allow functions
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// to be decoded before their context is complete. This will be true, for
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// example, for applications that wish to allow functions to refer to themselves.
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//
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// The simplest use of a ContextFunc is to give user functions access to the
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// same global variables and functions available elsewhere in an application's
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// configuration language, but more complex applications may use different
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// contexts to support lexical scoping depending on where in a configuration
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// structure a function declaration is found, etc.
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type ContextFunc func() *hcl.EvalContext
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// DecodeUserFunctions looks for blocks of the given type in the given body
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// and, for each one found, interprets it as a custom function definition.
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//
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// On success, the result is a mapping of function names to implementations,
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// along with a new body that represents the remaining content of the given
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// body which can be used for further processing.
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//
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// The result expression of each function is parsed during decoding but not
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// evaluated until the function is called.
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//
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// If the given ContextFunc is non-nil, it will be called to obtain the
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// context in which the function result expressions will be evaluated. If nil,
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// or if it returns nil, the result expression will have access only to
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// variables named after the declared parameters. A non-nil context turns
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// the returned functions into closures, bound to the given context.
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//
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// If the returned diagnostics set has errors then the function map and
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// remain body may be nil or incomplete.
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func DecodeUserFunctions(body hcl.Body, blockType string, context ContextFunc) (funcs map[string]function.Function, remain hcl.Body, diags hcl.Diagnostics) {
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return decodeUserFunctions(body, blockType, context)
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}
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