Package dev.frostlake.functions

Class TextArgumentFunction

java.lang.Object
dev.frostlake.functions.BuiltInFunction
dev.frostlake.functions.TextArgumentFunction
Direct Known Subclasses:
Ascii, BitLength, Char, CharIndex, Chr, Concat, ConcatWs, Contains, EditDistance, EndsWith, InitCap, Insert, JarowinklerSimilarity, Left, Len, Length, Lower, LPad, LTrim, NormalizeFn, OctetLength, ParseIp, ParseUrl, Position, RandStr, RegexpCount, RegexpInstr, RegexpLike, RegexpReplace, RegexpSubstr, RegexpSubstrAll, Repeat, Replace, Reverse, Right, RPad, RTrim, RtrimmedLength, Soundex, Space, Split, SplitPart, StartsWith, Strtok, StrtokToArray, Substring, Translate, Trim, TryParseIp, TryValidateUtf8, Unicode, Upper, ValidateUtf8
public abstract class TextArgumentFunction extends BuiltInFunction
A built-in that reads its arguments as text, and therefore refuses a statically OBJECT- or ARRAY-typed value in EVERY argument position.

Every position, not merely the string-shaped ones — that was measured rather than assumed. Live over an OBJECT column, all three of SPLIT_PART(o, ',', 1), SPLIT_PART(s, o, 1) and SPLIT_PART(s, ',', o) are argument-type errors, and so are LPAD(o, 20, '.'), LPAD(s, o, '.') (which live reports through SPACE) and LPAD(s, 20, o). A semi-structured value coerces to neither the VARCHAR nor the NUMBER these functions want, so the whole signature refuses it and the per-position distinction collapses.

Membership is by measurement, so two neighbours in the same package deliberately stay out: SEARCH ACCEPTS semi-structured data (SEARCH(o, 'k') returned TRUE live), and INSTR / CHAR_LENGTH / CHARACTER_LENGTH are names Snowflake does not know at all ("Unknown function"), so there is no live behaviour to copy. Extending this class is what declares the rule; nothing infers it from the package.

VARIANT is never refused, even when it holds an object — UPPER(vo) returned {"X":1} live — and neither is an explicit conversion: UPPER(o::VARCHAR), UPPER(TO_VARCHAR(o)) and UPPER(TO_JSON(o)) all work. The rule reads the DECLARED type, so UPPER(v::OBJECT) — the same value, cast — IS refused.

  • Constructor Details

    • TextArgumentFunction

      protected TextArgumentFunction(String name, DataType returnType)

  • Method Details

    • semiStructuredRejection

      public SemiStructuredRejection semiStructuredRejection(int position)
      Description copied from class: BuiltInFunction
      How argument position refuses a statically OBJECT- or ARRAY-typed value, or SemiStructuredRejection.NONE when it does not. Snowflake never implicitly coerces a semi-structured value to the VARCHAR (or NUMBER) a text or numeric function reads, so such an argument is an argument-type error at COMPILE time rather than a stringification or a fabricated zero: live, UPPER(o) over an OBJECT column is "Invalid argument types for function 'UPPER': (OBJECT)", SUM(o) is the same sentence for 'SUM', and SPLIT_PART(s, o, 1) names the position it was given. VARIANT is never refused, even when it holds an object.

      Declared HERE, on the function, rather than in a name-keyed table beside the rule: the registry is already the authority on a function's types (BuiltInFunction.getReturnType()), a declaration on the instance covers the function's ALIASES for free (SUBSTR and SUBSTRING are one object, and so are VARIANCE_POP and VAR_POP), and a per-position answer is the only shape that fits — ARRAY_TO_STRING(a, ',') takes an ARRAY in position 0 and refuses one in position 1.

      The answer is an ENUM rather than a boolean because Snowflake phrases the refusal three different ways, with three different SQLSTATEs — see SemiStructuredRejection.

      The default is NONE, meaning UNDECLARED rather than "accepts": a function that has not been measured against live Snowflake constrains nothing. Answering for every position is what TextArgumentFunction and NumericArgumentFunction exist for.

      Overrides:
      semiStructuredRejection in class BuiltInFunction
      Parameters:
      position - the zero-based argument position being asked about
      Returns:
      the refusal this position gives a semi-structured value, or NONE when undeclared

    • vectorRejection

      public SemiStructuredRejection vectorRejection(int position)
      A VECTOR is no text either, and is refused in every position (live-verified).
      Overrides:
      vectorRejection in class BuiltInFunction
      Parameters:
      position - the zero-based argument position being asked about
      Returns:
      the refusal this position gives a VECTOR value; by default none