basic/env.in.bas

   1
   2 REM ENV_NEW(O) -> R
   3 ENV_NEW:
   4   REM allocate the data hashmap
   5   GOSUB HASHMAP
   6   ET=R
   7
   8   REM set the outer and data pointer
   9   T=13:L=R:N=O:GOSUB ALLOC
  10   AY=ET:GOSUB RELEASE: REM environment takes ownership
  11   RETURN
  12
  13 REM see RELEASE types.in.bas for environment cleanup
  14
  15 REM ENV_NEW_BINDS(O, BI, EX) -> R
  16 ENV_NEW_BINDS:
  17   GOSUB ENV_NEW
  18   E=R
  19   REM process bindings
  20   ENV_NEW_BINDS_LOOP:
  21     IF Z%(BI,1)=0 THEN R=E:RETURN
  22     REM get/deref the key from BI
  23     R=BI+1:GOSUB DEREF_R
  24     K=R
  25
  26     IF S$(Z%(K,1))="&" THEN GOTO EVAL_NEW_BINDS_VARGS
  27
  28     EVAL_NEW_BINDS_1x1:
  29       REM get/deref the key from EX
  30       R=EX+1:GOSUB DEREF_R
  31       V=R
  32       REM set the binding in the environment data
  33       GOSUB ENV_SET
  34       REM go to next element of BI and EX
  35       BI=Z%(BI,1)
  36       EX=Z%(EX,1)
  37       GOTO ENV_NEW_BINDS_LOOP
  38
  39     EVAL_NEW_BINDS_VARGS:
  40       REM get/deref the key from next element of BI
  41       BI=Z%(BI,1)
  42       R=BI+1:GOSUB DEREF_R
  43       K=R
  44       REM the value is the remaining list in EX
  45       A=EX:T=6:GOSUB FORCE_SEQ_TYPE
  46       V=R
  47       REM set the binding in the environment data
  48       GOSUB ENV_SET
  49       R=E
  50       AY=V:GOSUB RELEASE: REM list is owned by environment
  51       RETURN
  52
  53 REM ENV_SET(E, K, V) -> R
  54 ENV_SET:
  55   H=Z%(E,1)
  56   GOSUB ASSOC1
  57   Z%(E,1)=R
  58   R=V
  59   RETURN
  60
  61 REM ENV_SET_S(E, K$, V) -> R
  62 ENV_SET_S:
  63   H=Z%(E,1)
  64   GOSUB ASSOC1_S
  65   Z%(E,1)=R
  66   R=V
  67   RETURN
  68
  69 REM ENV_FIND(E, K) -> R
  70 REM   Returns environment (R) containing K. If found, value found is
  71 REM   in T4
  72 SUB ENV_FIND
  73   EF=E
  74   ENV_FIND_LOOP:
  75     H=Z%(EF,1)
  76     REM More efficient to use GET for value (R) and contains? (T3)
  77     GOSUB HASHMAP_GET
  78     REM if we found it, save value in T4 for ENV_GET
  79     IF T3=1 THEN T4=R:GOTO ENV_FIND_DONE
  80     EF=Z%(EF+1,1): REM get outer environment
  81     IF EF<>-1 THEN GOTO ENV_FIND_LOOP
  82   ENV_FIND_DONE:
  83     R=EF
  84 END SUB
  85
  86 REM ENV_GET(E, K) -> R
  87 ENV_GET:
  88   CALL ENV_FIND
  89   IF R=-1 THEN R=0:ER=-1:ER$="'"+S$(Z%(K,1))+"' not found":GOTO ENV_GET_RETURN
  90   R=T4:GOSUB DEREF_R
  91   Z%(R,0)=Z%(R,0)+32
  92   GOTO ENV_GET_RETURN