-GOTO MAIN
-
-REM $INCLUDE: 'readline.in.bas'
-REM $INCLUDE: 'types.in.bas'
-REM $INCLUDE: 'reader.in.bas'
-REM $INCLUDE: 'printer.in.bas'
-REM $INCLUDE: 'env.in.bas'
-REM $INCLUDE: 'core.in.bas'
-
-REM $INCLUDE: 'debug.in.bas'
-
-REM READ(A$) -> R
-MAL_READ:
- GOSUB READ_STR
- RETURN
-
-REM EVAL_AST(A, E) -> R
-REM called using GOTO to avoid basic return address stack usage
-REM top of stack should have return label index
-EVAL_AST:
- REM push A and E on the stack
- X=X+2:S%(X-1)=E:S%(X)=A
-
- IF ER<>-2 THEN GOTO EVAL_AST_RETURN
-
- GOSUB DEREF_A
-
- T=Z%(A,0)AND15
- IF T=5 THEN GOTO EVAL_AST_SYMBOL
- IF T>=6 AND T<=8 THEN GOTO EVAL_AST_SEQ
-
- REM scalar: deref to actual value and inc ref cnt
- R=A:GOSUB DEREF_R
- Z%(R,0)=Z%(R,0)+16
- GOTO EVAL_AST_RETURN
-
- EVAL_AST_SYMBOL:
- K=A:GOSUB ENV_GET
- GOTO EVAL_AST_RETURN
-
- EVAL_AST_SEQ:
- REM allocate the first entry (T already set above)
- L=0:N=0:GOSUB ALLOC
-
- REM make space on the stack
- X=X+4
- REM push type of sequence
- S%(X-3)=T
- REM push sequence index
- S%(X-2)=-1
- REM push future return value (new sequence)
- S%(X-1)=R
- REM push previous new sequence entry
- S%(X)=R
-
- EVAL_AST_SEQ_LOOP:
- REM update index
- S%(X-2)=S%(X-2)+1
-
- REM check if we are done evaluating the source sequence
- IF Z%(A,1)=0 THEN GOTO EVAL_AST_SEQ_LOOP_DONE
-
- REM if hashmap, skip eval of even entries (keys)
- IF (S%(X-3)=8) AND ((S%(X-2) AND 1)=0) THEN GOTO EVAL_AST_DO_REF
- GOTO EVAL_AST_DO_EVAL
-
- EVAL_AST_DO_REF:
- R=A+1:GOSUB DEREF_R: REM deref to target of referred entry
- Z%(R,0)=Z%(R,0)+16: REM inc ref cnt of referred value
- GOTO EVAL_AST_ADD_VALUE
-
- EVAL_AST_DO_EVAL:
- REM call EVAL for each entry
- A=A+1:GOSUB EVAL
- A=A-1
- GOSUB DEREF_R: REM deref to target of evaluated entry
-
- EVAL_AST_ADD_VALUE:
-
- REM update previous value pointer to evaluated entry
- Z%(S%(X)+1,1)=R
-
- IF ER<>-2 THEN GOTO EVAL_AST_SEQ_LOOP_DONE
-
- REM allocate the next entry
- REM same new sequence entry type
- T=S%(X-3):L=0:N=0:GOSUB ALLOC
-
- REM update previous sequence entry value to point to new entry
- Z%(S%(X),1)=R
- REM update previous ptr to current entry
- S%(X)=R
-
- REM process the next sequence entry from source list
- A=Z%(A,1)
-
- GOTO EVAL_AST_SEQ_LOOP
- EVAL_AST_SEQ_LOOP_DONE:
- REM if no error, get return value (new seq)
- IF ER=-2 THEN R=S%(X-1)
- REM otherwise, free the return value and return nil
- IF ER<>-2 THEN R=0:AY=S%(X-1):GOSUB RELEASE
-
- REM pop previous, return, index and type
- X=X-4
- GOTO EVAL_AST_RETURN
-
- EVAL_AST_RETURN:
- REM pop A and E off the stack
- E=S%(X-1):A=S%(X):X=X-2
-
- REM pop EVAL AST return label/address
- RN%=S%(X):X=X-1
- ON RN% GOTO EVAL_AST_RETURN_1,EVAL_AST_RETURN_2,EVAL_AST_RETURN_3
- RETURN
-
-REM EVAL(A, E)) -> R
-EVAL:
- LV=LV+1: REM track basic return stack level
-
- REM push A and E on the stack
- X=X+2:S%(X-1)=E:S%(X)=A
-
- EVAL_TCO_RECUR:
-
- REM AZ=A:PR=1:GOSUB PR_STR
- REM PRINT "EVAL: "+R$+" [A:"+STR$(A)+", LV:"+STR$(LV)+"]"
-
- GOSUB DEREF_A
-
- GOSUB LIST_Q
- IF R THEN GOTO APPLY_LIST
- REM ELSE
- REM push EVAL_AST return label/address
- X=X+1:S%(X)=1
- GOTO EVAL_AST
- EVAL_AST_RETURN_1:
-
- GOTO EVAL_RETURN
-
- APPLY_LIST:
- GOSUB EMPTY_Q
- IF R THEN R=A:Z%(R,0)=Z%(R,0)+16:GOTO EVAL_RETURN
-
- A0%=A+1
- R=A0%:GOSUB DEREF_R:A0%=R
-
- REM get symbol in A$
- IF (Z%(A0%,0)AND15)<>5 THEN A$=""
- IF (Z%(A0%,0)AND15)=5 THEN A$=S$(Z%(A0%,1))
-
- IF A$="def!" THEN GOTO EVAL_DEF
- IF A$="let*" THEN GOTO EVAL_LET
- IF A$="do" THEN GOTO EVAL_DO
- IF A$="if" THEN GOTO EVAL_IF
- IF A$="fn*" THEN GOTO EVAL_FN
- GOTO EVAL_INVOKE
-
- EVAL_GET_A3:
- A3%=Z%(Z%(Z%(A,1),1),1)+1
- R=A3%:GOSUB DEREF_R:A3%=R
- EVAL_GET_A2:
- A2%=Z%(Z%(A,1),1)+1
- R=A2%:GOSUB DEREF_R:A2%=R
- EVAL_GET_A1:
- A1%=Z%(A,1)+1
- R=A1%:GOSUB DEREF_R:A1%=R
- RETURN
-
- EVAL_DEF:
- REM PRINT "def!"
- GOSUB EVAL_GET_A2: REM set a1% and a2%
-
- X=X+1:S%(X)=A1%: REM push A1%
- A=A2%:GOSUB EVAL: REM eval a2
- A1%=S%(X):X=X-1: REM pop A1%
-
- IF ER<>-2 THEN GOTO EVAL_RETURN
-
- REM set a1 in env to a2
- K=A1%:V=R:GOSUB ENV_SET
- GOTO EVAL_RETURN
-
- EVAL_LET:
- REM PRINT "let*"
- GOSUB EVAL_GET_A2: REM set a1% and a2%
-
- X=X+1:S%(X)=A2%: REM push/save A2%
- X=X+1:S%(X)=E: REM push env for for later release
-
- REM create new environment with outer as current environment
- O=E:GOSUB ENV_NEW
- E=R
- EVAL_LET_LOOP:
- IF Z%(A1%,1)=0 THEN GOTO EVAL_LET_LOOP_DONE
-
- X=X+1:S%(X)=A1%: REM push A1%
- REM eval current A1 odd element
- A=Z%(A1%,1)+1:GOSUB EVAL
- A1%=S%(X):X=X-1: REM pop A1%
-
- REM set environment: even A1% key to odd A1% eval'd above
- K=A1%+1:V=R:GOSUB ENV_SET
- AY=R:GOSUB RELEASE: REM release our use, ENV_SET took ownership
-
- REM skip to the next pair of A1% elements
- A1%=Z%(Z%(A1%,1),1)
- GOTO EVAL_LET_LOOP
-
- EVAL_LET_LOOP_DONE:
- E4%=S%(X):X=X-1: REM pop previous env
-
- REM release previous environment if not the current EVAL env
- IF E4%<>S%(X-2) THEN AY=E4%:GOSUB RELEASE
-
- A2%=S%(X):X=X-1: REM pop A2%
- A=A2%:GOTO EVAL_TCO_RECUR: REM TCO loop
-
- EVAL_DO:
- A=Z%(A,1): REM rest
-
- REM TODO: TCO
-
- REM push EVAL_AST return label/address
- X=X+1:S%(X)=2
- GOTO EVAL_AST
- EVAL_AST_RETURN_2:
-
- X=X+1:S%(X)=R: REM push eval'd list
- A=R:GOSUB LAST: REM return the last element
- AY=S%(X):X=X-1: REM pop eval'd list
- GOSUB RELEASE: REM release the eval'd list
- GOTO EVAL_RETURN
-
- EVAL_IF:
- GOSUB EVAL_GET_A1: REM set a1%
- REM push A
- X=X+1:S%(X)=A
- A=A1%:GOSUB EVAL
- REM pop A
- A=S%(X):X=X-1
- IF (R=0) OR (R=1) THEN GOTO EVAL_IF_FALSE
-
- EVAL_IF_TRUE:
- AY=R:GOSUB RELEASE
- GOSUB EVAL_GET_A2: REM set a1% and a2% after EVAL
- A=A2%:GOTO EVAL_TCO_RECUR: REM TCO loop
- EVAL_IF_FALSE:
- AY=R:GOSUB RELEASE
- REM if no false case (A3%), return nil
- IF Z%(Z%(Z%(A,1),1),1)=0 THEN R=0:GOTO EVAL_RETURN
- GOSUB EVAL_GET_A3: REM set a1% - a3% after EVAL
- A=A3%:GOTO EVAL_TCO_RECUR: REM TCO loop
-
- EVAL_FN:
- GOSUB EVAL_GET_A2: REM set a1% and a2%
- A=A2%:P=A1%:GOSUB MAL_FUNCTION
- GOTO EVAL_RETURN
-
- EVAL_INVOKE:
- REM push EVAL_AST return label/address
- X=X+1:S%(X)=3
- GOTO EVAL_AST
- EVAL_AST_RETURN_3:
-
- REM if error, return f/args for release by caller
- IF ER<>-2 THEN GOTO EVAL_RETURN
-
- REM push f/args for release after call
- X=X+1:S%(X)=R
-
- F=R+1
-
- AR=Z%(R,1): REM rest
- R=F:GOSUB DEREF_R:F=R
-
- IF (Z%(F,0)AND15)=9 THEN GOTO EVAL_DO_FUNCTION
- IF (Z%(F,0)AND15)=10 THEN GOTO EVAL_DO_MAL_FUNCTION
-
- REM if error, pop and return f/args for release by caller
- R=S%(X):X=X-1
- ER=-1:ER$="apply of non-function":GOTO EVAL_RETURN
-
- EVAL_DO_FUNCTION:
- GOSUB DO_FUNCTION
-
- REM pop and release f/args
- AY=S%(X):X=X-1:GOSUB RELEASE
- GOTO EVAL_RETURN
-
- EVAL_DO_MAL_FUNCTION:
- E4%=E: REM save the current environment for release
-
- REM create new environ using env stored with function
- O=Z%(F+1,1):BI%=Z%(F+1,0):EX%=AR:GOSUB ENV_NEW_BINDS
-
- REM release previous env if it is not the top one on the
- REM stack (S%(X-2)) because our new env refers to it and
- REM we no longer need to track it (since we are TCO recurring)
- IF E4%<>S%(X-2) THEN AY=E4%:GOSUB RELEASE
-
- REM claim the AST before releasing the list containing it
- A=Z%(F,1):Z%(A,0)=Z%(A,0)+16
- REM add AST to pending release queue to free as soon as EVAL
- REM actually returns (LV+1)
- ZM%=ZM%+1:ZR%(ZM%,0)=A:ZR%(ZM%,1)=LV+1
-
- REM pop and release f/args
- AY=S%(X):X=X-1:GOSUB RELEASE
-
- REM A set above
- E=R:GOTO EVAL_TCO_RECUR: REM TCO loop
-
- EVAL_RETURN:
- REM AZ=R: PR=1: GOSUB PR_STR
- REM PRINT "EVAL_RETURN R: ["+R$+"] ("+STR$(R)+"), LV:"+STR$(LV)+",ER:"+STR$(ER)
-
- REM release environment if not the top one on the stack
- IF E<>S%(X-1) THEN AY=E:GOSUB RELEASE
-
- LV=LV-1: REM track basic return stack level
-
- REM release everything we couldn't release earlier
- GOSUB RELEASE_PEND
-
- REM trigger GC
- TA%=FRE(0)
-
- REM pop A and E off the stack
- E=S%(X-1):A=S%(X):X=X-2
-
- RETURN
-
-REM PRINT(A) -> R$
-MAL_PRINT:
- AZ=A:PR=1:GOSUB PR_STR
- RETURN
-
-REM RE(A$) -> R
-REM Assume RE% has repl_env
-REM caller must release result
-RE:
- R1=0
- GOSUB MAL_READ
- R1=R
- IF ER<>-2 THEN GOTO REP_DONE
-
- A=R:E=RE%:GOSUB EVAL
-
- REP_DONE:
- REM Release memory from MAL_READ
- IF R1<>0 THEN AY=R1:GOSUB RELEASE
- RETURN: REM caller must release result of EVAL
-
-REM REP(A$) -> R$
-REM Assume RE% has repl_env
-REP:
- R1=0:R2=0
- GOSUB MAL_READ
- R1=R
- IF ER<>-2 THEN GOTO REP_DONE
-
- A=R:E=RE%:GOSUB EVAL
- R2=R
- IF ER<>-2 THEN GOTO REP_DONE
-
- A=R:GOSUB MAL_PRINT
- RT$=R$
-
- REP_DONE:
- REM Release memory from MAL_READ and EVAL
- IF R2<>0 THEN AY=R2:GOSUB RELEASE
- IF R1<>0 THEN AY=R1:GOSUB RELEASE
- R$=RT$
- RETURN
-
-REM MAIN program
-MAIN:
- GOSUB INIT_MEMORY
-
- LV=0
-
- REM create repl_env
- O=-1:GOSUB ENV_NEW:RE%=R
-
- REM core.EXT: defined in Basic
- E=RE%:GOSUB INIT_CORE_NS: REM set core functions in repl_env
-
- ZT%=ZI: REM top of memory after base repl_env
-
- REM core.mal: defined using the language itself
- A$="(def! not (fn* (a) (if a false true)))"
- GOSUB RE:AY=R:GOSUB RELEASE
-
- REPL_LOOP:
- A$="user> ":GOSUB READLINE: REM call input parser
- IF EOF=1 THEN GOTO QUIT
-
- A$=R$:GOSUB REP: REM call REP
-
- IF ER<>-2 THEN GOSUB PRINT_ERROR:GOTO REPL_LOOP
- PRINT R$
- GOTO REPL_LOOP
-
- QUIT:
- REM P1%=ZT%: P2%=-1: GOSUB PR_MEMORY
- GOSUB PR_MEMORY_SUMMARY
- END
-
- PRINT_ERROR:
- PRINT "Error: "+ER$
- ER=-2:ER$=""
- RETURN
-
+GOTO MAIN
+
+REM $INCLUDE: 'mem.in.bas'
+REM $INCLUDE: 'types.in.bas'
+REM $INCLUDE: 'readline.in.bas'
+REM $INCLUDE: 'reader.in.bas'
+REM $INCLUDE: 'printer.in.bas'
+REM $INCLUDE: 'env.in.bas'
+REM $INCLUDE: 'core.in.bas'
+
+REM $INCLUDE: 'debug.in.bas'
+
+REM READ(A$) -> R
+MAL_READ:
+ GOSUB READ_STR
+ RETURN
+
+REM EVAL_AST(A, E) -> R
+SUB EVAL_AST
+ REM push A and E on the stack
+ Q=E:GOSUB PUSH_Q
+ GOSUB PUSH_A
+
+ IF ER<>-2 THEN GOTO EVAL_AST_RETURN
+
+ GOSUB TYPE_A
+ IF T=5 THEN GOTO EVAL_AST_SYMBOL
+ IF T>=6 AND T<=8 THEN GOTO EVAL_AST_SEQ
+
+ REM scalar: deref to actual value and inc ref cnt
+ R=A
+ GOSUB INC_REF_R
+ GOTO EVAL_AST_RETURN
+
+ EVAL_AST_SYMBOL:
+ K=A:GOTO ENV_GET
+ ENV_GET_RETURN:
+ GOTO EVAL_AST_RETURN
+
+ EVAL_AST_SEQ:
+ REM setup the stack for the loop
+ GOSUB MAP_LOOP_START
+
+ EVAL_AST_SEQ_LOOP:
+ REM check if we are done evaluating the source sequence
+ IF Z%(A+1)=0 THEN GOTO EVAL_AST_SEQ_LOOP_DONE
+
+ REM if we are returning to DO, then skip last element
+ REM The EVAL_DO call to EVAL_AST must be call #2 for EVAL_AST to
+ REM return early and for TCO to work
+ Q=5:GOSUB PEEK_Q_Q
+ IF Q=2 AND Z%(Z%(A+1)+1)=0 THEN GOTO EVAL_AST_SEQ_LOOP_DONE
+
+ REM call EVAL for each entry
+ GOSUB PUSH_A
+ IF T<>8 THEN A=Z%(A+2)
+ IF T=8 THEN A=Z%(A+3)
+ Q=T:GOSUB PUSH_Q: REM push/save type
+ CALL EVAL
+ GOSUB POP_Q:T=Q: REM pop/restore type
+ GOSUB POP_A
+ M=R
+
+ REM if error, release the unattached element
+ REM TODO: is R=0 correct?
+ IF ER<>-2 THEN AY=R:GOSUB RELEASE:R=0:GOTO EVAL_AST_SEQ_LOOP_DONE
+
+ REM for hash-maps, copy the key (inc ref since we are going to
+ REM release it below)
+ IF T=8 THEN N=M:M=Z%(A+2):Z%(M)=Z%(M)+32
+
+
+ REM update the return sequence structure
+ REM release N (and M if T=8) since seq takes full ownership
+ C=1:GOSUB MAP_LOOP_UPDATE
+
+ REM process the next sequence entry from source list
+ A=Z%(A+1)
+
+ GOTO EVAL_AST_SEQ_LOOP
+ EVAL_AST_SEQ_LOOP_DONE:
+ REM cleanup stack and get return value
+ GOSUB MAP_LOOP_DONE
+ GOTO EVAL_AST_RETURN
+
+ EVAL_AST_RETURN:
+ REM pop A and E off the stack
+ GOSUB POP_A
+ GOSUB POP_Q:E=Q
+END SUB
+
+REM EVAL(A, E) -> R
+SUB EVAL
+ LV=LV+1: REM track basic return stack level
+
+ REM push A and E on the stack
+ Q=E:GOSUB PUSH_Q
+ GOSUB PUSH_A
+
+ REM PRINT "EVAL A:"+STR$(A)+",X:"+STR$(X)+",LV:"+STR$(LV)+",FRE:"+STR$(FRE(0))
+
+ EVAL_TCO_RECUR:
+
+ IF ER<>-2 THEN GOTO EVAL_RETURN
+
+ REM AZ=A:B=1:GOSUB PR_STR
+ REM PRINT "EVAL: "+R$+" [A:"+STR$(A)+", LV:"+STR$(LV)+"]"
+
+ GOSUB LIST_Q
+ IF R THEN GOTO APPLY_LIST
+ REM ELSE
+ CALL EVAL_AST
+ GOTO EVAL_RETURN
+
+ APPLY_LIST:
+ GOSUB EMPTY_Q
+ IF R THEN R=A:GOSUB INC_REF_R:GOTO EVAL_RETURN
+
+ A0=Z%(A+2)
+
+ REM get symbol in A$
+ IF (Z%(A0)AND 31)<>5 THEN A$=""
+ IF (Z%(A0)AND 31)=5 THEN A$=S$(Z%(A0+1))
+
+ IF A$="def!" THEN GOTO EVAL_DEF
+ IF A$="let*" THEN GOTO EVAL_LET
+ IF A$="do" THEN GOTO EVAL_DO
+ IF A$="if" THEN GOTO EVAL_IF
+ IF A$="fn*" THEN GOTO EVAL_FN
+ GOTO EVAL_INVOKE
+
+ EVAL_GET_A3:
+ A3=Z%(Z%(Z%(Z%(A+1)+1)+1)+2)
+ EVAL_GET_A2:
+ A2=Z%(Z%(Z%(A+1)+1)+2)
+ EVAL_GET_A1:
+ A1=Z%(Z%(A+1)+2)
+ RETURN
+
+ EVAL_DEF:
+ REM PRINT "def!"
+ GOSUB EVAL_GET_A2: REM set A1 and A2
+
+ Q=A1:GOSUB PUSH_Q
+ A=A2:CALL EVAL: REM eval a2
+ GOSUB POP_Q:A1=Q
+
+ IF ER<>-2 THEN GOTO EVAL_RETURN
+
+ REM set a1 in env to a2
+ K=A1:C=R:GOSUB ENV_SET
+ GOTO EVAL_RETURN
+
+ EVAL_LET:
+ REM PRINT "let*"
+ GOSUB EVAL_GET_A2: REM set A1 and A2
+
+ Q=A2:GOSUB PUSH_Q: REM push/save A2
+ Q=E:GOSUB PUSH_Q: REM push env for for later release
+
+ REM create new environment with outer as current environment
+ C=E:GOSUB ENV_NEW
+ E=R
+ EVAL_LET_LOOP:
+ IF Z%(A1+1)=0 THEN GOTO EVAL_LET_LOOP_DONE
+
+ Q=A1:GOSUB PUSH_Q: REM push A1
+ REM eval current A1 odd element
+ A=Z%(Z%(A1+1)+2):CALL EVAL
+ GOSUB POP_Q:A1=Q: REM pop A1
+
+ IF ER<>-2 THEN GOTO EVAL_LET_LOOP_DONE
+
+ REM set key/value in the environment
+ K=Z%(A1+2):C=R:GOSUB ENV_SET
+ AY=R:GOSUB RELEASE: REM release our use, ENV_SET took ownership
+
+ REM skip to the next pair of A1 elements
+ A1=Z%(Z%(A1+1)+1)
+ GOTO EVAL_LET_LOOP
+
+ EVAL_LET_LOOP_DONE:
+ GOSUB POP_Q:AY=Q: REM pop previous env
+
+ REM release previous environment if not the current EVAL env
+ GOSUB PEEK_Q_2
+ IF AY<>Q THEN GOSUB RELEASE
+
+ GOSUB POP_Q:A2=Q: REM pop A2
+ A=A2:GOTO EVAL_TCO_RECUR: REM TCO loop
+
+ EVAL_DO:
+ A=Z%(A+1): REM rest
+ GOSUB PUSH_A: REM push/save A
+
+ REM this must be EVAL_AST call #2 for EVAL_AST to return early
+ REM and for TCO to work
+ CALL EVAL_AST
+
+ REM cleanup
+ AY=R: REM get eval'd list for release
+
+ GOSUB POP_A: REM pop/restore original A for LAST
+ GOSUB LAST: REM get last element for return
+ A=R: REM new recur AST
+
+ REM cleanup
+ GOSUB RELEASE: REM release eval'd list
+ AY=A:GOSUB RELEASE: REM release LAST value (not sure why)
+
+ GOTO EVAL_TCO_RECUR: REM TCO loop
+
+ EVAL_IF:
+ GOSUB EVAL_GET_A1: REM set A1
+ GOSUB PUSH_A: REM push/save A
+ A=A1:CALL EVAL
+ GOSUB POP_A: REM pop/restore A
+ IF (R=0) OR (R=2) THEN GOTO EVAL_IF_FALSE
+
+ EVAL_IF_TRUE:
+ AY=R:GOSUB RELEASE
+ GOSUB EVAL_GET_A2: REM set A1 and A2 after EVAL
+ A=A2:GOTO EVAL_TCO_RECUR: REM TCO loop
+ EVAL_IF_FALSE:
+ AY=R:GOSUB RELEASE
+ REM if no false case (A3), return nil
+ GOSUB COUNT
+ IF R<4 THEN R=0:GOSUB INC_REF_R:GOTO EVAL_RETURN
+ GOSUB EVAL_GET_A3: REM set A1 - A3 after EVAL
+ A=A3:GOTO EVAL_TCO_RECUR: REM TCO loop
+
+ EVAL_FN:
+ GOSUB EVAL_GET_A2: REM set A1 and A2
+ T=10:L=A2:M=A1:N=E:GOSUB ALLOC: REM mal function
+ GOTO EVAL_RETURN
+
+ EVAL_INVOKE:
+ CALL EVAL_AST
+
+ REM if error, return f/args for release by caller
+ IF ER<>-2 THEN GOTO EVAL_RETURN
+
+ REM push f/args for release after call
+ GOSUB PUSH_R
+
+ AR=Z%(R+1): REM rest
+ F=Z%(R+2)
+
+ REM if metadata, get the actual object
+ GOSUB TYPE_F
+ IF T=14 THEN F=Z%(F+1):GOSUB TYPE_F
+
+ ON T-8 GOTO EVAL_DO_FUNCTION,EVAL_DO_MAL_FUNCTION,EVAL_DO_MAL_FUNCTION
+
+ REM if error, pop and return f/args for release by caller
+ GOSUB POP_R
+ ER=-1:E$="apply of non-function":GOTO EVAL_RETURN
+
+ EVAL_DO_FUNCTION:
+ REM regular function
+ IF Z%(F+1)<60 THEN GOSUB DO_FUNCTION:GOTO EVAL_DO_FUNCTION_SKIP
+ REM for recur functions (apply, map, swap!), use GOTO
+ IF Z%(F+1)>60 THEN CALL DO_TCO_FUNCTION
+ EVAL_DO_FUNCTION_SKIP:
+
+ REM pop and release f/args
+ GOSUB POP_Q:AY=Q
+ GOSUB RELEASE
+ GOTO EVAL_RETURN
+
+ EVAL_DO_MAL_FUNCTION:
+ Q=E:GOSUB PUSH_Q: REM save the current environment for release
+
+ REM create new environ using env and params stored in function
+ C=Z%(F+3):A=Z%(F+2):B=AR:GOSUB ENV_NEW_BINDS
+
+ REM release previous env if it is not the top one on the
+ REM stack (X%(X-2)) because our new env refers to it and
+ REM we no longer need to track it (since we are TCO recurring)
+ GOSUB POP_Q:AY=Q
+ GOSUB PEEK_Q_2
+ IF AY<>Q THEN GOSUB RELEASE
+
+ REM claim the AST before releasing the list containing it
+ A=Z%(F+1):Z%(A)=Z%(A)+32
+ REM add AST to pending release queue to free as soon as EVAL
+ REM actually returns (LV+1)
+ LV=LV+1:GOSUB PEND_A_LV:LV=LV-1
+
+ REM pop and release f/args
+ GOSUB POP_Q:AY=Q
+ GOSUB RELEASE
+
+ REM A set above
+ E=R:GOTO EVAL_TCO_RECUR: REM TCO loop
+
+ EVAL_RETURN:
+ REM AZ=R: B=1: GOSUB PR_STR
+ REM PRINT "EVAL_RETURN R: ["+R$+"] ("+STR$(R)+"), LV:"+STR$(LV)+",ER:"+STR$(ER)
+
+ REM release environment if not the top one on the stack
+ GOSUB PEEK_Q_1
+ IF E<>Q THEN AY=E:GOSUB RELEASE
+
+ LV=LV-1: REM track basic return stack level
+
+ REM release everything we couldn't release earlier
+ GOSUB RELEASE_PEND
+
+ REM trigger GC
+ #cbm T=FRE(0)
+ #qbasic T=0
+
+ REM pop A and E off the stack
+ GOSUB POP_A
+ GOSUB POP_Q:E=Q
+
+END SUB
+
+REM PRINT(A) -> R$
+MAL_PRINT:
+ AZ=A:B=1:GOSUB PR_STR
+ RETURN
+
+REM RE(A$) -> R
+REM Assume D has repl_env
+REM caller must release result
+RE:
+ R1=-1
+ GOSUB MAL_READ
+ R1=R
+ IF ER<>-2 THEN GOTO RE_DONE
+
+ A=R:E=D:CALL EVAL
+
+ RE_DONE:
+ REM Release memory from MAL_READ
+ AY=R1:GOSUB RELEASE
+ RETURN: REM caller must release result of EVAL
+
+REM REP(A$) -> R$
+REM Assume D has repl_env
+SUB REP
+ R2=-1
+
+ GOSUB RE
+ R2=R
+ IF ER<>-2 THEN GOTO REP_DONE
+
+ A=R:GOSUB MAL_PRINT
+
+ REP_DONE:
+ REM Release memory from MAL_READ and EVAL
+ AY=R2:GOSUB RELEASE
+END SUB
+
+REM MAIN program
+MAIN:
+ GOSUB INIT_MEMORY
+
+ LV=0
+
+ REM create repl_env
+ C=0:GOSUB ENV_NEW:D=R
+
+ REM core.EXT: defined in Basic
+ E=D:GOSUB INIT_CORE_NS: REM set core functions in repl_env
+
+ ZT=ZI: REM top of memory after base repl_env
+
+ REM core.mal: defined using the language itself
+ A$="(def! not (fn* (a) (if a false true)))"
+ GOSUB RE:AY=R:GOSUB RELEASE
+
+ REPL_LOOP:
+ A$="user> ":GOSUB READLINE: REM call input parser
+ IF EZ=1 THEN GOTO QUIT
+ IF R$="" THEN GOTO REPL_LOOP
+
+ A$=R$:CALL REP: REM call REP
+
+ IF ER<>-2 THEN GOSUB PRINT_ERROR:GOTO REPL_LOOP
+ PRINT R$
+ GOTO REPL_LOOP
+
+ QUIT:
+ REM GOSUB PR_MEMORY_SUMMARY_SMALL
+ #cbm END
+ #qbasic SYSTEM
+
+ PRINT_ERROR:
+ PRINT "Error: "+E$
+ ER=-2:E$=""
+ RETURN
+
HCoop / jackhill / mal.git / blobdiff