PuduLangLog.Expressions.Functions

type: module path: "@root/src/PuduLangLog/Expressions/Functions.pudu" fidelity: Active grammar: "[[grammar/pudu]]" depth_score: 0.6 depth_status: MEDIUM tags: [module, expressions] aliases: [PuduLangLog.Expressions.Functions]

Purpose

The built-in functions: text search and slicing, regular expressions, Length, ElementAt, TypeOf, TagOf, ToString, Round, Coalesce, IsDefined, Undefined, Now, UtcDateTime, Nest, and Inspect.

Interface

Signatures

export fn isKnown(name: Str) -> Bool

export fn call(name: Str, arguments: &Array[Option[Log.Value]], ignoring: Bool, now: &Log.Timestamp) -> Option[Log.Value]

export fn elementAt(target: &Log.Value, key: &Log.Value, ignoring: Bool) -> Option[Log.Value]

Linkage

• Requires: [[src/PuduLangLog]], [[src/PuduLangLog/Domain/Properties]], [[src/PuduLangLog/Expressions/Values]], Std.Decimal, Std.List, Std.Math, Std.Option, Std.Regex, Std.Text.
• Consumed by: [[src/PuduLangLog/Expressions/Evaluator]] and [[src/PuduLangLog/Expressions]].

Algorithm

1. Names are matched in lower case; isKnown answers for compile-time checks.
2. An undefined argument makes the call undefined, except for Coalesce, IsDefined, TypeOf, Undefined, and Now.
3. ci lowers both sides of text comparisons and lowers a pattern's literal letters while keeping its escapes.
4. TypeOf names scalars by their Pudu type and collections as array, object, or dictionary; an undefined argument is undefined.

Negative Logic (Prohibited Paths)

• A regular expression that does not compile is undefined, never an error.

Edge Cases

• Substring with a start past the end is undefined.

Depth

DEPTH 0.6 (MEDIUM). Tested by test/PuduLangLog/ExpressionsTest.

Grill Log

• Q: Why does TypeOf accept undefined? A: Asking whether something is missing is the question most filters on optional properties ask. _Rejected:_ undefined in, undefined out, which makes the check impossible.

Referenced by

[[CHANGELOG]] · [[src/PuduLangLog/_MOC]] · [[src/PuduLangLog/Expressions]] · [[src/PuduLangLog/Expressions/Evaluator]] · [[src/PuduLangLog/Expressions/Values]] · [[subsystems/Expressions]]