54 lines
1.8 KiB
Crystal
54 lines
1.8 KiB
Crystal
require "./label"
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module Spectator
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# Represents an expression from a test.
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# This is typically captured by an `expect` macro.
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# It consists of a label and the value of the expression.
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# The label should be a string recognizable by the user,
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# or nil if one isn't available.
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#
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# This base class is provided so that all generic sub-classes can be stored as this one type.
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# The value of the expression can be retrieved by down-casting to the expected type with `#cast`.
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#
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# NOTE: This is intentionally a class and not a struct.
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# If it were a struct, changes made to the value held by an instance may not be kept when passing it around.
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# See commit ca564619ad2ae45f832a058d514298c868fdf699.
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abstract class AbstractExpression
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# User recognizable string for the expression.
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# This can be something like a variable name or a snippet of Crystal code.
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getter label : Label
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# Creates the expression.
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# The *label* is usually the Crystal code evaluating to the `#raw_value`.
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# It can be nil if it isn't available.
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def initialize(@label : Label)
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end
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# Retrieves the evaluated value of the expression.
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abstract def raw_value
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# Attempts to cast `#raw_value` to the type *T* and return it.
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def cast(type : T.class) : T forall T
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raw_value.as(T)
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end
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# Produces a string representation of the expression.
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# This consists of the label (if one is available) and the value.
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def to_s(io)
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if (label = @label)
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io << label << ": "
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end
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raw_value.to_s(io)
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end
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# Produces a detailed string representation of the expression.
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# This consists of the label (if one is available) and the value.
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def inspect(io)
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if (label = @label)
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io << label << ": "
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end
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raw_value.inspect(io)
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end
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end
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end
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