From 691031a7f9bc8aa4d5fa160155c632b2728efb12 Mon Sep 17 00:00:00 2001
From: Eremey Valetov <eremey@valetov.com>
Date: Sun, 15 Feb 2026 16:22:55 -0500
Subject: [PATCH] Fix RESTORE with line number, add 8 Rosetta Code test
 programs

RESTORE n now correctly positions past the DATA token so the next
READ gets actual values instead of the token byte.

New tests: Roman numerals, Luhn validator, Towers of Hanoi, 100 Doors,
Pascal's triangle, type declarations, Hailstone sequence, multiplication
table.  50 tests now pass.
---
 src/interp.c                       | 16 ++++++++++++++++
 tests/programs/def_types.bas       | 29 +++++++++++++++++++++++++++++
 tests/programs/hailstone.bas       | 13 +++++++++++++
 tests/programs/hanoi.bas           | 22 ++++++++++++++++++++++
 tests/programs/hundred_doors.bas   | 17 +++++++++++++++++
 tests/programs/luhn.bas            | 21 +++++++++++++++++++++
 tests/programs/mult_table.bas      | 22 ++++++++++++++++++++++
 tests/programs/pascal_triangle.bas | 21 +++++++++++++++++++++
 tests/programs/roman_numerals.bas  | 24 ++++++++++++++++++++++++
 9 files changed, 185 insertions(+)
 create mode 100644 tests/programs/def_types.bas
 create mode 100644 tests/programs/hailstone.bas
 create mode 100644 tests/programs/hanoi.bas
 create mode 100644 tests/programs/hundred_doors.bas
 create mode 100644 tests/programs/luhn.bas
 create mode 100644 tests/programs/mult_table.bas
 create mode 100644 tests/programs/pascal_triangle.bas
 create mode 100644 tests/programs/roman_numerals.bas

diff --git a/src/interp.c b/src/interp.c
index cbf2e23..e386d90 100644
--- a/src/interp.c
+++ b/src/interp.c
@@ -279,6 +279,22 @@ static void stmt_restore(void)
         if (!gw.data_line_ptr)
             gw_error(ERR_UL);
         gw.data_ptr = gw.data_line_ptr->tokens;
+        /* Scan to the DATA token and skip past it so read_data_item
+           finds values, not the keyword.  If the target line has no
+           DATA, data_ptr ends at '\0' and the next READ will call
+           advance_data_ptr to move to subsequent lines. */
+        while (*gw.data_ptr && *gw.data_ptr != TOK_DATA) {
+            if (*gw.data_ptr == '"') {
+                gw.data_ptr++;
+                while (*gw.data_ptr && *gw.data_ptr != '"')
+                    gw.data_ptr++;
+                if (*gw.data_ptr == '"') gw.data_ptr++;
+                continue;
+            }
+            gw.data_ptr++;
+        }
+        if (*gw.data_ptr == TOK_DATA)
+            gw.data_ptr++;
     } else {
         gw.data_line_ptr = NULL;
         gw.data_ptr = NULL;
diff --git a/tests/programs/def_types.bas b/tests/programs/def_types.bas
new file mode 100644
index 0000000..bd1a9d8
--- /dev/null
+++ b/tests/programs/def_types.bas
@@ -0,0 +1,29 @@
+10 REM Type declarations, RESTORE with line#, ON GOSUB
+20 DEFINT A-C
+30 DEFSNG D-F
+40 DEFSTR S-T
+50 A = 3.7
+60 IF A <> 4 THEN PRINT "FAIL: DEFINT A should round 3.7 to 4, got"; A : END
+70 D = 3.14159
+80 IF D < 3.14 OR D > 3.15 THEN PRINT "FAIL: DEFSNG D unexpected"; D : END
+90 S = "hello"
+100 IF S <> "hello" THEN PRINT "FAIL: DEFSTR S should hold string" : END
+110 REM RESTORE with line number
+120 DATA 10, 20, 30
+200 DATA 40, 50, 60
+210 RESTORE 200
+220 READ X
+230 IF X <> 40 THEN PRINT "FAIL: RESTORE 200 should read 40, got"; X : END
+240 RESTORE 120
+250 READ Y
+260 IF Y <> 10 THEN PRINT "FAIL: RESTORE 120 should read 10, got"; Y : END
+270 REM ON GOSUB
+280 FOR I = 1 TO 3
+290   ON I GOSUB 400, 410, 420
+300 NEXT I
+310 IF R <> 6 THEN PRINT "FAIL: ON GOSUB sum should be 6, got"; R : END
+320 PRINT "Type declarations OK"
+330 END
+400 R = R + 1 : RETURN
+410 R = R + 2 : RETURN
+420 R = R + 3 : RETURN
diff --git a/tests/programs/hailstone.bas b/tests/programs/hailstone.bas
new file mode 100644
index 0000000..233cd69
--- /dev/null
+++ b/tests/programs/hailstone.bas
@@ -0,0 +1,13 @@
+10 REM Hailstone (Collatz) sequence - Rosetta Code
+20 N# = 27
+30 STEPS = 0
+40 MAXVAL# = N#
+50 WHILE N# <> 1
+60   IF N# / 2 = INT(N# / 2) THEN N# = N# / 2 ELSE N# = 3 * N# + 1
+70   STEPS = STEPS + 1
+80   IF N# > MAXVAL# THEN MAXVAL# = N#
+90 WEND
+100 REM Hailstone(27) has 111 steps, max value 9232
+110 IF STEPS <> 111 THEN PRINT "FAIL: expected 111 steps, got"; STEPS : END
+120 IF MAXVAL# <> 9232 THEN PRINT "FAIL: expected max 9232, got"; MAXVAL# : END
+130 PRINT "Hailstone OK: 27 ->"; STEPS; "steps, max"; MAXVAL#
diff --git a/tests/programs/hanoi.bas b/tests/programs/hanoi.bas
new file mode 100644
index 0000000..7849da7
--- /dev/null
+++ b/tests/programs/hanoi.bas
@@ -0,0 +1,22 @@
+10 REM Towers of Hanoi - iterative with explicit stack - Rosetta Code
+20 NDISKS = 4
+30 DIM SN(50), SF(50), ST(50), SV(50)
+40 SP = 0
+50 REM Push initial call: move NDISKS from A to C via B
+60 SP = SP + 1 : SN(SP) = NDISKS : SF(SP) = 1 : ST(SP) = 3 : SV(SP) = 2
+70 MOVES = 0
+80 IF SP = 0 THEN 200
+90 N = SN(SP) : F = SF(SP) : T = ST(SP) : V = SV(SP) : SP = SP - 1
+100 IF N = 0 THEN 80
+110 REM Push move(N-1, via, to, from) - this goes on stack FIRST (executed LAST)
+120 SP = SP + 1 : SN(SP) = N-1 : SF(SP) = V : ST(SP) = T : SV(SP) = F
+130 REM Push the actual move of disk N from F to T (sentinel N=0 above it)
+140 SP = SP + 1 : SN(SP) = 0 : SF(SP) = F : ST(SP) = T : SV(SP) = 0
+150 MOVES = MOVES + 1
+160 REM Push move(N-1, from, via, to)
+170 SP = SP + 1 : SN(SP) = N-1 : SF(SP) = F : ST(SP) = V : SV(SP) = T
+180 GOTO 80
+200 REM Should be 2^NDISKS - 1 = 15 moves
+210 EXPECTED = 2^NDISKS - 1
+220 IF MOVES <> EXPECTED THEN PRINT "FAIL: expected"; EXPECTED; "got"; MOVES : END
+230 PRINT "Hanoi OK:"; MOVES; "moves"
diff --git a/tests/programs/hundred_doors.bas b/tests/programs/hundred_doors.bas
new file mode 100644
index 0000000..877304b
--- /dev/null
+++ b/tests/programs/hundred_doors.bas
@@ -0,0 +1,17 @@
+10 REM 100 Doors problem - Rosetta Code
+20 DIM D(100)
+30 FOR PASS = 1 TO 100
+40   FOR DOOR = PASS TO 100 STEP PASS
+50     D(DOOR) = 1 - D(DOOR)
+60   NEXT DOOR
+70 NEXT PASS
+80 REM Only perfect squares should be open
+90 C = 0
+100 FOR I = 1 TO 100
+110   IF D(I) = 0 THEN 150
+120   S = SQR(I)
+130   IF INT(S) <> S THEN PRINT "FAIL: door"; I; "open but not perfect square" : END
+140   C = C + 1
+150 NEXT I
+160 IF C <> 10 THEN PRINT "FAIL: expected 10 open doors, got"; C : END
+170 PRINT "100 Doors OK:"; C; "open"
diff --git a/tests/programs/luhn.bas b/tests/programs/luhn.bas
new file mode 100644
index 0000000..6f43d62
--- /dev/null
+++ b/tests/programs/luhn.bas
@@ -0,0 +1,21 @@
+10 REM Luhn algorithm - credit card validator - Rosetta Code
+20 DATA "49927398716", 1, "49927398717", 0
+30 DATA "1234567812345670", 1, "1234567812345678", 0
+40 FOR T = 1 TO 4
+50 READ CARD$
+60 S = 0
+70 NDIG = LEN(CARD$)
+80 PARITY = NDIG MOD 2
+90 FOR I = 1 TO NDIG
+100   D = VAL(MID$(CARD$, I, 1))
+110   IF ((I-1) MOD 2) <> PARITY THEN 140
+120   D = D * 2
+130   IF D > 9 THEN D = D - 9
+140   S = S + D
+150 NEXT I
+160 RESULT = 0
+170 IF (S MOD 10) = 0 THEN RESULT = 1
+180 READ EXPECTED
+190 IF RESULT <> EXPECTED THEN PRINT "FAIL: "; CARD$; " sum="; S : END
+200 NEXT T
+210 PRINT "Luhn OK"
diff --git a/tests/programs/mult_table.bas b/tests/programs/mult_table.bas
new file mode 100644
index 0000000..ea1f799
--- /dev/null
+++ b/tests/programs/mult_table.bas
@@ -0,0 +1,22 @@
+10 REM Multiplication table - Rosetta Code
+20 REM Header row
+30 PRINT "  X";
+40 FOR J = 1 TO 12
+50   PRINT USING "####"; J;
+60 NEXT J
+70 PRINT
+80 PRINT STRING$(51, "-");
+90 PRINT
+100 REM Table body
+110 CHECKSUM = 0
+120 FOR I = 1 TO 12
+130   PRINT USING "###"; I;
+140   FOR J = 1 TO 12
+150     IF J < I THEN PRINT "    "; ELSE PRINT USING "####"; I * J;
+160     IF J >= I THEN CHECKSUM = CHECKSUM + I * J
+170   NEXT J
+180   PRINT
+190 NEXT I
+200 REM Sum of i*j for j>=i, i=1..12: known value 3367
+210 IF CHECKSUM <> 3367 THEN PRINT "FAIL: checksum"; CHECKSUM : END
+220 PRINT "Multiplication table OK"
diff --git a/tests/programs/pascal_triangle.bas b/tests/programs/pascal_triangle.bas
new file mode 100644
index 0000000..197dc25
--- /dev/null
+++ b/tests/programs/pascal_triangle.bas
@@ -0,0 +1,21 @@
+10 REM Pascal's triangle - Rosetta Code
+20 NROWS = 8
+30 DIM R(20)
+40 FOR ROW = 0 TO NROWS - 1
+50   REM Build row right-to-left to avoid overwriting
+60   R(ROW) = 1
+65   IF ROW < 2 THEN 100
+70   FOR J = ROW - 1 TO 1 STEP -1
+80     R(J) = R(J) + R(J-1)
+90   NEXT J
+100  R(0) = 1
+110  REM Print with spacing
+120  PRINT SPACE$(2 * (NROWS - ROW));
+130  FOR J = 0 TO ROW
+140    PRINT USING "####"; R(J);
+150  NEXT J
+160  PRINT
+170 NEXT ROW
+180 REM Verify a known value: row 7, col 3 = C(7,3) = 35
+190 IF R(3) <> 35 THEN PRINT "FAIL: C(7,3) should be 35, got"; R(3) : END
+200 PRINT "Pascal's triangle OK"
diff --git a/tests/programs/roman_numerals.bas b/tests/programs/roman_numerals.bas
new file mode 100644
index 0000000..d2e78b3
--- /dev/null
+++ b/tests/programs/roman_numerals.bas
@@ -0,0 +1,24 @@
+10 REM Roman numeral encoder - Rosetta Code
+20 DIM V(12), R$(12)
+30 DATA 1000,"M",900,"CM",500,"D",400,"CD"
+40 DATA 100,"C",90,"XC",50,"L",40,"XL"
+50 DATA 10,"X",9,"IX",5,"V",4,"IV",1,"I"
+60 FOR I = 0 TO 12
+70 READ V(I), R$(I)
+80 NEXT I
+90 DATA 1990, 2008, 1666, 3999, 42, 14
+100 FOR T = 1 TO 6
+110 READ N
+120 ORIG = N
+130 S$ = ""
+140 I = 0
+150 WHILE N > 0
+160   WHILE N >= V(I)
+170     S$ = S$ + R$(I)
+180     N = N - V(I)
+190   WEND
+200   I = I + 1
+210 WEND
+220 PRINT ORIG; "="; S$
+230 NEXT T
+240 PRINT "Roman numerals OK"