| 1 | # | 
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| 2 | # local variables: | 
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| 3 | #       o The keyword will make sure the variable is defined in | 
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| 4 | #     current variable context instead of the global one. | 
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| 5 | #   o Local variables are readable by children but not writable, | 
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| 6 | #     writes goes to the globle space (a sideeffect / feature). | 
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| 7 | #   o Local variables hides global and parent variables. | 
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| 8 | # | 
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| 9 |  | 
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| 10 |  | 
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| 11 | # global variable. | 
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| 12 | var_exists1 = 1 | 
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| 13 |  | 
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| 14 |  | 
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| 15 |  | 
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| 16 | ## | 
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| 17 | # A simple define that is $(eval)uated. | 
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| 18 | define def_test1 | 
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| 19 |  | 
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| 20 | # check that the existing variable is accessible. | 
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| 21 | ifneq ($(var_exists1),1) | 
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| 22 | $(error var_exists1=$(var_exists1) (def_test1/1)) | 
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| 23 | endif | 
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| 24 |  | 
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| 25 | # Quick check with a couple of local variables. | 
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| 26 | local var_local1 = 2 | 
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| 27 | ifneq ($(var_local1),2) | 
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| 28 | $(error var_local1=$(var_local1) (def_test1/2)) | 
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| 29 | endif | 
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| 30 | local var_local2 = 3 | 
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| 31 | ifneq ($(var_local2),3) | 
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| 32 | $(error var_local2=$(var_local2) (def_test1/3)) | 
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| 33 | endif | 
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| 34 |  | 
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| 35 | # var_local1 and var_local2 should remain unchanged, var_local3 shouldn't exist. | 
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| 36 | $(evalctx $(value def_test2)) | 
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| 37 |  | 
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| 38 | ifneq ($(var_local1),2) | 
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| 39 | $(error var_local1=$(var_local1) (def_test1/4)) | 
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| 40 | endif | 
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| 41 | ifneq ($(var_local2),3) | 
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| 42 | $(error var_local2=$(var_local2) (def_test1/5)) | 
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| 43 | endif | 
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| 44 | ifneq ($(var_local3),) | 
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| 45 | $(error var_local3=$(var_local3) (def_test1/6)) | 
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| 46 | endif | 
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| 47 |  | 
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| 48 | endef # def_test1 | 
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| 49 |  | 
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| 50 |  | 
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| 51 |  | 
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| 52 | ## | 
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| 53 | # Called by def_test1, this checks that the locals of def_test1 | 
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| 54 | # are accessible and can be hidden by another local variable | 
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| 55 | # or updated if assigned to. | 
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| 56 | define def_test2 | 
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| 57 |  | 
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| 58 | # check that the existing variables are accessible, including the def_test1 ones. | 
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| 59 | ifneq ($(var_exists1),1) | 
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| 60 | $(error var_exists1=$(var_exists1) (def_test2/1)) | 
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| 61 | endif | 
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| 62 | ifneq ($(var_local1),2) | 
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| 63 | $(error var_local1=$(var_local1) (def_test2/2)) | 
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| 64 | endif | 
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| 65 | ifneq ($(var_local2),3) | 
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| 66 | $(error var_local2=$(var_local2) (def_test2/3)) | 
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| 67 | endif | 
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| 68 |  | 
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| 69 | # Make a local var_local1 that hides the one in def_test1. | 
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| 70 | local var_local1 = 20 | 
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| 71 | ifneq ($(var_local1),20) | 
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| 72 | $(error var_local1=$(var_local1) (def_test2/4)) | 
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| 73 | endif | 
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| 74 |  | 
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| 75 | # FEATURE: Update the var_local2 variable, this should be visible in the global space and not the local. | 
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| 76 | var_local2 = 30 | 
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| 77 | ifneq ($(var_local2),3) | 
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| 78 | $(error var_local2=$(var_local2) (def_test2/5)) | 
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| 79 | endif | 
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| 80 |  | 
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| 81 | # create a new local variable that isn't accessible from def_test1. | 
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| 82 | local var_local3 = 4 | 
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| 83 | ifneq ($(var_local3),4) | 
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| 84 | $(error var_local3=$(var_local3) (def_test2/6)) | 
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| 85 | endif | 
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| 86 |  | 
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| 87 | endef # def_test2 | 
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| 88 |  | 
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| 89 |  | 
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| 90 |  | 
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| 91 | # | 
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| 92 | # The test body | 
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| 93 | # | 
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| 94 |  | 
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| 95 | # None of the local variables should exist. | 
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| 96 | ifneq ($(var_local1),) | 
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| 97 | $(error var_local1=$(var_local1)) | 
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| 98 | endif | 
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| 99 | ifneq ($(var_local2),) | 
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| 100 | $(error var_local2=$(var_local2)) | 
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| 101 | endif | 
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| 102 | ifneq ($(var_local3),) | 
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| 103 | $(error var_local3=$(var_local3)) | 
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| 104 | endif | 
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| 105 |  | 
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| 106 | # Evaluate the function in a local context. | 
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| 107 | $(evalctx $(value def_test1)) | 
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| 108 |  | 
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| 109 | # FEATURE: see var_local2 = 30 in def_test2. | 
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| 110 | ifneq ($(var_local2),30) | 
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| 111 | $(error var_local2=$(var_local2)) | 
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| 112 | endif | 
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| 113 |  | 
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| 114 | # None of the other local variables should exist. | 
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| 115 | ifneq ($(var_local1),) | 
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| 116 | $(error var_local1=$(var_local1)) | 
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| 117 | endif | 
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| 118 | ifneq ($(var_local3),) | 
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| 119 | $(error var_local3=$(var_local3)) | 
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| 120 | endif | 
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| 121 |  | 
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| 122 |  | 
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| 123 |  | 
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| 124 | # dummy | 
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| 125 | all: | 
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| 126 | echo local variables works. | 
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| 127 |  | 
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