basic/env.in.bas

   1
   2 REM ENV_NEW(C) -> R
   3 ENV_NEW:
   4   REM allocate the data hashmap
   5   GOSUB HASHMAP
   6   AY=R
   7
   8   REM set the outer and data pointer
   9   T=13:L=R:M=C:GOSUB ALLOC
  10   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(C, A, B) -> R
  16 ENV_NEW_BINDS:
  17   GOSUB ENV_NEW
  18   E=R
  19   REM process bindings
  20   ENV_NEW_BINDS_LOOP:
  21     IF Z%(A+1)=0 THEN R=E:RETURN
  22     REM get/deref the key from A
  23     K=Z%(A+2)
  24
  25     IF S$(Z%(K+1))="&" THEN GOTO EVAL_NEW_BINDS_VARGS
  26
  27     EVAL_NEW_BINDS_1x1:
  28       REM get/deref the key from B
  29       C=Z%(B+2)
  30       REM set the binding in the environment data
  31       GOSUB ENV_SET
  32       REM go to next element of A and B
  33       A=Z%(A+1)
  34       B=Z%(B+1)
  35       GOTO ENV_NEW_BINDS_LOOP
  36
  37     EVAL_NEW_BINDS_VARGS:
  38       REM get/deref the key from next element of A
  39       A=Z%(A+1)
  40       K=Z%(A+2)
  41       REM the value is the remaining list in B
  42       A=B:T=6:GOSUB FORCE_SEQ_TYPE
  43       C=R
  44       REM set the binding in the environment data
  45       GOSUB ENV_SET
  46       R=E
  47       AY=C:GOSUB RELEASE: REM list is owned by environment
  48       RETURN
  49
  50 REM ENV_SET(E, K, C) -> R
  51 ENV_SET:
  52   H=Z%(E+1)
  53   GOSUB ASSOC1
  54   Z%(E+1)=R
  55   R=C
  56   RETURN
  57
  58 REM ENV_SET_S(E, B$, C) -> R
  59 ENV_SET_S:
  60   H=Z%(E+1)
  61   GOSUB ASSOC1_S
  62   Z%(E+1)=R
  63   R=C
  64   RETURN
  65
  66 REM ENV_FIND(E, K) -> R
  67 REM   Returns environment (R) containing K. If found, value found is
  68 REM   in R4
  69 SUB ENV_FIND
  70   T=E
  71   ENV_FIND_LOOP:
  72     H=Z%(T+1)
  73     REM More efficient to use GET for value (R) and contains? (R3)
  74     GOSUB HASHMAP_GET
  75     REM if we found it, save value in R4 for ENV_GET
  76     IF R3=1 THEN R4=R:R=T:GOTO ENV_FIND_DONE
  77     T=Z%(T+2): REM get outer environment
  78     IF T>0 THEN GOTO ENV_FIND_LOOP
  79     R=-1
  80   ENV_FIND_DONE:
  81 END SUB
  82
  83 REM ENV_GET(E, K) -> R
  84 ENV_GET:
  85   CALL ENV_FIND
  86   IF R=-1 THEN ER=-1:E$="'"+S$(Z%(K+1))+"' not found":GOTO ENV_GET_RETURN
  87   R=R4
  88   GOSUB INC_REF_R
  89   GOTO ENV_GET_RETURN