feat(evaluator): Add REPT, EXACT, PROPER, CLEAN, CHAR, CODE, T, N

[arcaputo3]

Summary

Add secondary text functions for advanced text processing.

Functions to Implement

Function	Description	Excel Signature
REPT(text, n)	Repeat text n times	REPT(text, number_times)
EXACT(text1, text2)	Case-sensitive compare	EXACT(text1, text2)
PROPER(text)	Title Case	PROPER(text)
CLEAN(text)	Remove non-printable chars	CLEAN(text)
CHAR(n)	Character from code	CHAR(number)
CODE(text)	Code from first character	CODE(text)
T(value)	Convert to text if not already	T(value)
N(value)	Convert to number if not already	N(value)

Implementation Notes

REPT

• REPT("*", 5) → "*****"
• n must be >= 0

EXACT

• Returns TRUE/FALSE
• Case-sensitive: EXACT("Hello", "hello") → FALSE

PROPER

• PROPER("hello WORLD") → "Hello World"
• Handles apostrophes: "o'brien" → "O'Brien"

CLEAN

• Removes characters 0-31 (control characters)
• Preserves char 32+ (printable)

CHAR/CODE

• Uses ASCII/Unicode
• CHAR(65) → "A", CODE("A") → 65

T

• Returns text if input is text, empty string otherwise
• T("hello") → "hello", T(123) → ""

N

• Returns number if input is number, 0 otherwise
• N(123) → 123, N("hello") → 0, N(TRUE) → 1

Test Cases

REPT("*", 5) == "*****"
EXACT("Hello", "hello") == false
PROPER("hello WORLD") == "Hello World"
CLEAN("hello" + char(7) + "world") == "helloworld"
CHAR(65) == "A"
CODE("ABC") == 65
T("hello") == "hello"
T(123) == ""
N(123) == 123
N("hello") == 0

Priority

Low - Secondary text functions

Milestone

v0.6.0

[arcaputo3]

Closing as duplicate of #75 — these 8 functions (REPT, EXACT, PROPER, CLEAN, CHAR, CODE, T, N) are a subset of the P2 text functions tracked there.