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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