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mirror of https://github.com/kanaka/mal.git synced 2024-09-19 09:38:28 +03:00
mal/impls/basic/step5_tco.in.bas
Nicolas Boulenguez fbfe6784d2 Change quasiquote algorithm
- Add a `vec` built-in function in step7 so that `quasiquote` does not
  require `apply` from step9.
- Introduce quasiquoteexpand special in order to help debugging step7.
  This may also prepare newcomers to understand step8.
- Add soft tests.
- Do not quote numbers, strings and so on.

Should ideally have been in separate commits:
- elisp: simplify and fix (keyword :k)
- factor: fix copy/paste error in let*/step7, simplify eval-ast.
- guile: improve list/vector types
- haskell: revert evaluation during quasiquote
- logo, make: cosmetic issues
2020-08-11 01:01:56 +02:00

396 lines
9.4 KiB
QBasic
Executable File

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$="apply of non-function":GOTO EVAL_RETURN
EVAL_DO_FUNCTION:
REM regular function
IF Z%(F+1)<65 THEN GOSUB DO_FUNCTION:GOTO EVAL_DO_FUNCTION_SKIP
REM for recur functions (apply, map, swap!), use GOTO
IF Z%(F+1)>64 THEN CALL DO_TCO_FUNCTION
EVAL_DO_FUNCTION_SKIP:
REM pop and release f/args
GOSUB POP_Q:AY=Q
GOSUB RELEASE
GOTO EVAL_RETURN
EVAL_DO_MAL_FUNCTION:
Q=E:GOSUB PUSH_Q: REM save the current environment for release
REM create new environ using env and params stored in function
C=Z%(F+3):A=Z%(F+2):B=AR:GOSUB ENV_NEW_BINDS
REM release previous env if it is not the top one on the
REM stack (X%(X-2)) because our new env refers to it and
REM we no longer need to track it (since we are TCO recurring)
GOSUB POP_Q:AY=Q
GOSUB PEEK_Q_2
IF AY<>Q THEN GOSUB RELEASE
REM claim the AST before releasing the list containing it
A=Z%(F+1):Z%(A)=Z%(A)+32
REM add AST to pending release queue to free as soon as EVAL
REM actually returns (LV+1)
LV=LV+1:GOSUB PEND_A_LV:LV=LV-1
REM pop and release f/args
GOSUB POP_Q:AY=Q
GOSUB RELEASE
REM A set above
E=R:GOTO EVAL_TCO_RECUR: REM TCO loop
EVAL_RETURN:
REM AZ=R: B=1: GOSUB PR_STR
REM PRINT "EVAL_RETURN R: ["+R$+"] ("+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