Word Images

Word Images is a random sentence generator that constructs grammatically structured phrases from six word categories: nouns, verbs, adjectives, adverbs, prepositions, and objects. The user supplies a slash-separated sequence of category numbers (e.g., “3/1/2/4”) to define sentence order, or presses ENTER to cycle through seven preset templates stored at lines 8001–8007. Words are selected from DATA lists of 20 entries each using a probabilistic loop: each word has a 1-in-10 chance of being chosen per iteration, giving a non-uniform distribution biased toward later entries in the list. The program includes an automatic insertion of the object category (6) whenever a preposition (5) is selected, achieved by string manipulation at line 122. Generated sentences are displayed one character per PRINT statement, with spaces triggering newlines to produce a vertical word-stack visual effect.

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Program Structure

The program divides into four logical regions:

1. Initialisation and UI (lines 10–100): defines named line-number constants for each DATA block, displays instructions, and accepts the user’s sentence-order string.
2. Sentence assembly (lines 105–145): iterates over characters in A$, dispatching to word-selection subroutines at 1000×VAL A$(X).
3. Display (lines 200–230): prints the assembled sentence vertically, one character per loop iteration, using spaces as line-break triggers.
4. Word data (lines 9000–9050): six DATA statements of 20 words each, addressed via RESTORE to named line-number variables.

Key BASIC Idioms

Several memory-efficiency and readability techniques appear throughout:

• Named line constants: NOUN=9000, VERB=9010, etc. allow RESTORE NOUN instead of bare line numbers, improving readability at no extra cost since the variables hold integers.
• GO SUB 1000*VAL A$(X): computes the subroutine address arithmetically from the digit character in A$, replacing a multi-branch IF chain with a single dispatch line (line 140).
• GO TO 1001*VAL A$(X) (line 1030): similarly recycles the current digit to generate a fallback jump address (1001, 2002, etc.) when the random selection loop exhausts all 20 words — though see the bug note below.
• Shared subroutine body: all six word-category subroutines share the loop at lines 1015–1025 by falling through with GO TO 1015, keeping code compact.

Sentence Construction and the Preposition Auto-Insert

When a “5” (preposition) is encountered during the setup scan (lines 120–122), the program injects “/6” immediately after it in A$, ensuring an object always follows a preposition. The counter C is advanced past the newly inserted characters so the injection loop does not re-process them. Line 6000 additionally prepends ” THE” to the accumulated string before selecting the object word, producing constructs like “IN THE CAVE”.

Word Selection Algorithm

The selection loop (lines 1015–1025) reads each of the 20 words in a category and accepts it with probability 1/10 (INT(RND*10)=3). This means:

• Earlier words in a list are less likely to be chosen than later ones, since the loop can only stop at a word it reaches.
• There is a (9/10)^20 ≈ 12% chance that no word is accepted on a full pass, triggering the fallback at line 1030.
• A uniform selection would require INT(RND*20)+1 with direct array access, but DATA/​RESTORE requires sequential reading, making this probabilistic approach a reasonable trade-off.

Vertical Display Effect

Lines 205–220 walk through S$ character by character. A space character triggers a bare PRINT (newline) rather than printing the space itself, so each word of the sentence appears on its own line. This gives the “word image” visual style referenced in the program title. Pressing SPACE at line 225 restarts the entire program via RUN.

Preset Sentence Templates

Line	Template	Structure
8001	1/2/1/5/6	NOUN VERB NOUN PREP OBJECT
8002	3/1/5/6/4/2/1/5/6	ADJ NOUN PREP OBJ ADV VERB NOUN PREP OBJ
8003	3/1/2/4	ADJ NOUN VERB ADV
8004	1/2	NOUN VERB
8005	1/5/6/2/1	NOUN PREP OBJ VERB NOUN
8006	1/5/6/2/4	NOUN PREP OBJ VERB ADV
8007	3/1/4/2/1/5/6	ADJ NOUN ADV VERB NOUN PREP OBJ

When P=1 (computer-selection mode), line 235 chooses a template randomly with GO TO 8001+INT(RND*7), cycling through all seven presets with equal probability.