45 lines
1.3 KiB
Go
45 lines
1.3 KiB
Go
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package hcl
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// ExprMap tests if the given expression is a static map construct and,
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// if so, extracts the expressions that represent the map elements.
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// If the given expression is not a static map, error diagnostics are
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// returned.
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//
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// A particular Expression implementation can support this function by
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// offering a method called ExprMap that takes no arguments and returns
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// []KeyValuePair. This method should return nil if a static map cannot
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// be extracted. Alternatively, an implementation can support
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// UnwrapExpression to delegate handling of this function to a wrapped
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// Expression object.
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func ExprMap(expr Expression) ([]KeyValuePair, Diagnostics) {
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type exprMap interface {
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ExprMap() []KeyValuePair
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}
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physExpr := UnwrapExpressionUntil(expr, func(expr Expression) bool {
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_, supported := expr.(exprMap)
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return supported
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})
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if exM, supported := physExpr.(exprMap); supported {
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if pairs := exM.ExprMap(); pairs != nil {
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return pairs, nil
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}
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}
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return nil, Diagnostics{
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&Diagnostic{
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Severity: DiagError,
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Summary: "Invalid expression",
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Detail: "A static map expression is required.",
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Subject: expr.StartRange().Ptr(),
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},
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}
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}
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// KeyValuePair represents a pair of expressions that serve as a single item
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// within a map or object definition construct.
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type KeyValuePair struct {
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Key Expression
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Value Expression
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}
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