Lollipops

Lollipops is an arcade-style game where the player guides a lollipop sprite horizontally sweeping back and forth across a colorful field, using Q/Z keys or a joystick to move it up and down and collect flavored candies. The program uses ATTR to read the paper color of cells the lollipop passes through, mapping each color to a candy flavor and score value (licorice scores 49, down to lemon at 1), while a white/bright cell acts as a peppermint that ends the game. STICK(1,1) and STICK(2,1) calls provide joystick support alongside keyboard input. The field is populated by PAPER-colored spaces printed with a skewed RND*RND distribution to bias toward lower-numbered colors, plus a set of bright white spaces representing peppermints. The game tracks 300 sweep steps before forcing game over, and scoring uses the formula (7-1)^2 applied uniformly rather than per-flavor, suggesting a placeholder or simplified scoring scheme.

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Program Analysis

Program Structure

The program is organized into several functional blocks:

1. Lines 5–10: Title REM and initialization jump to subroutine 300 (banner) then randomize and jump to instructions at 420.
2. Lines 30–60: Field setup — clears screen, places bright white peppermint cells, then floods the field with colored candy cells.
3. Lines 70–190: Main game loop — moves the lollipop, detects collisions via ATTR, updates score, enforces timer.
4. Lines 200–240: Game-over display and replay prompt.
5. Line 300: Title banner subroutine.
6. Lines 420–510: Instruction screens with flavor score table.
7. Lines 8999–9000: STOP and SAVE/VERIFY.

Field Generation

The candy field is built in two passes. First, lines 35 places 10 bright white spaces (PAPER 7, BRIGHT 1) at random positions — these are the peppermints. Then line 50 prints 75 colored spaces using PAPER 6-INT(7*RND*RND), which uses a squared RND to bias the distribution toward higher paper colors (i.e., lighter flavors are more common than licorice/black).

Lollipop Movement and Direction

The lollipop bounces horizontally: variable k holds the direction (+1 or -1). Line 100 reverses k when column c goes out of bounds. The sprite is drawn as the string "--O" (moving right) or "O--" (moving left) using Boolean string multiplication, a common Sinclair BASIC idiom. The previous position stored in ll/cc is erased with three spaces each frame.

ATTR-Based Collision Detection

Line 130 reads the screen attribute at the leading edge of the lollipop using ATTR(l, ...). The column expression ((c+2) AND k=1)+(c AND k=-1) selects the tip of the lollipop depending on travel direction. The raw ATTR value is divided by 8 to extract the paper color (bits 3–5). A value ≤ 6 indicates a colored candy; a value of 15 indicates a bright white peppermint (ATTR = 15×8 = 120… actually PAPER 7 + BRIGHT = attribute byte with paper=7 and bright=1, giving value 7 + 8×7 = 63; divided by 8 = 7, not 15 — see anomaly note below).

Scoring Anomaly

Line 140 adds to score s using (7-1)^2, which always equals 36 regardless of candy color. The instructions describe a flavor-dependent scoring table (licorice 49, grape 36, cherry 25, etc.) suggesting the score should use (7-a)^2 where a is the paper color, but the variable a is not used in the formula. This is a bug — the intended expression was almost certainly (7-a)^2.

Peppermint Detection Anomaly

Line 145 checks a=15 to detect the peppermint. Since a = ATTR(l,col)/8, a value of 15 would require ATTR = 120, corresponding to PAPER 7 + BRIGHT 1 (paper=7, bright set, ink=0). The ATTR byte for PAPER 7 BRIGHT 1 is indeed 7*8 + 64 = 120, and 120/8 = 15, so this check is mathematically correct despite the use of integer division.

Input Handling

Both keyboard and joystick are supported simultaneously. STICK(1,1) reads the left joystick port. Vertical movement (line 110) uses Boolean arithmetic: the lollipop moves down if Z is pressed or joystick returns 2, and up if Q is pressed or joystick returns 1, with boundary clamping to rows 1–20. POKE 23658,8 at line 95 enables CAPS SHIFT + symbol shift behavior (caps lock) so that lowercase Z input is handled correctly each loop iteration.

Key Variables

Variable	Purpose
l, c	Current row and column of lollipop
ll, cc	Previous position (for erasing)
k	Horizontal direction (+1 right, -1 left)
p	Pop count (number of candies tasted)
s	Score (bugged — always adds 36)
t	Timer (game ends at 300)
a	Detected paper color at lollipop tip

Notable Techniques

• Boolean string selection: ("--O" AND k=1)+("O--" AND k=-1) cleanly selects the directional sprite without an IF statement.
• Squared RND distribution (RND*RND) for biased random field coloring.
• ATTR read divided by 8 to isolate paper color is a well-known Sinclair idiom for color-based collision detection.
• The title subroutine at line 300 is reused between the instruction screens for consistent presentation.
• The typo “LOLIPOPS” (one L) in the line 300 banner versus “LOLLIPOPS” in the line 5 REM and the filename is a minor inconsistency, as is “TNE” instead of “THE” in line 495.