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105 lines
3.6 KiB
Plaintext
105 lines
3.6 KiB
Plaintext
;; ifTrue: / ifFalse: / ifTrue:ifFalse: / ifFalse:ifTrue: tests.
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;;
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;; In Smalltalk these are *block sends* on Boolean. The runtime can
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;; intrinsify the dispatch in the JIT (already provided by the bytecode
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;; expansion infrastructure) but the spec semantics are: True/False
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;; receive these messages and pick which branch block to evaluate.
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(set! st-test-pass 0)
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(set! st-test-fail 0)
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(set! st-test-fails (list))
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(st-bootstrap-classes!)
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(define ev (fn (src) (smalltalk-eval src)))
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(define evp (fn (src) (smalltalk-eval-program src)))
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;; ── 1. ifTrue: ──
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(st-test "true ifTrue: → block value" (ev "true ifTrue: [42]") 42)
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(st-test "false ifTrue: → nil" (ev "false ifTrue: [42]") nil)
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;; ── 2. ifFalse: ──
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(st-test "true ifFalse: → nil" (ev "true ifFalse: [42]") nil)
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(st-test "false ifFalse: → block value" (ev "false ifFalse: [42]") 42)
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;; ── 3. ifTrue:ifFalse: ──
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(st-test "true ifTrue:ifFalse:" (ev "true ifTrue: [1] ifFalse: [2]") 1)
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(st-test "false ifTrue:ifFalse:" (ev "false ifTrue: [1] ifFalse: [2]") 2)
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;; ── 4. ifFalse:ifTrue: (reversed-order keyword) ──
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(st-test "true ifFalse:ifTrue:" (ev "true ifFalse: [1] ifTrue: [2]") 2)
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(st-test "false ifFalse:ifTrue:" (ev "false ifFalse: [1] ifTrue: [2]") 1)
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;; ── 5. The non-taken branch is NOT evaluated (laziness) ──
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(st-test
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"ifTrue: doesn't evaluate the false branch"
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(evp
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"| ran |
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ran := false.
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true ifTrue: [99] ifFalse: [ran := true. 0].
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^ ran")
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false)
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(st-test
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"ifFalse: doesn't evaluate the true branch"
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(evp
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"| ran |
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ran := false.
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false ifTrue: [ran := true. 99] ifFalse: [0].
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^ ran")
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false)
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;; ── 6. Branch result type can be anything ──
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(st-test "branch returns string" (ev "true ifTrue: ['yes'] ifFalse: ['no']") "yes")
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(st-test "branch returns nil" (ev "true ifTrue: [nil] ifFalse: [99]") nil)
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(st-test "branch returns array" (ev "false ifTrue: [#(1)] ifFalse: [#(2 3)]") (list 2 3))
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;; ── 7. Nested if ──
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(st-test
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"nested ifTrue:ifFalse:"
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(evp
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"| x |
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x := 5.
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^ x > 0
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ifTrue: [x > 10
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ifTrue: [#big]
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ifFalse: [#smallPositive]]
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ifFalse: [#nonPositive]")
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(make-symbol "smallPositive"))
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;; ── 8. Branch reads outer locals (closure semantics) ──
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(st-test
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"branch closes over outer bindings"
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(evp
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"| label x |
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x := 7.
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label := x > 0
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ifTrue: [#positive]
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ifFalse: [#nonPositive].
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^ label")
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(make-symbol "positive"))
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;; ── 9. and: / or: short-circuit ──
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(st-test "and: short-circuits when receiver false"
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(ev "false and: [1/0]") false)
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(st-test "and: with true receiver runs second" (ev "true and: [42]") 42)
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(st-test "or: short-circuits when receiver true"
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(ev "true or: [1/0]") true)
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(st-test "or: with false receiver runs second" (ev "false or: [99]") 99)
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;; ── 10. & and | are eager (not blocks) ──
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(st-test "& on booleans" (ev "true & true") true)
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(st-test "| on booleans" (ev "false | true") true)
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;; ── 11. Boolean negation ──
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(st-test "not on true" (ev "true not") false)
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(st-test "not on false" (ev "false not") true)
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;; ── 12. Real-world idiom: max via ifTrue:ifFalse: in a method ──
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(st-class-define! "Mathy" "Object" (list))
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(st-class-add-method! "Mathy" "myMax:and:"
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(st-parse-method "myMax: a and: b ^ a > b ifTrue: [a] ifFalse: [b]"))
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(st-test "method using ifTrue:ifFalse: returns max" (evp "^ Mathy new myMax: 3 and: 7") 7)
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(st-test "method using ifTrue:ifFalse: returns max sym" (evp "^ Mathy new myMax: 9 and: 4") 9)
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(list st-test-pass st-test-fail)
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