Appendix C: Function Reference

TL;DR

This appendix is a function checklist, not a tutorial. Pair it with chapter examples when you need behavioral context.

You can inspect the runtime list with:

./build/markql --mode plain --color=disabled --query "SHOW FUNCTIONS;"

Extraction

• TEXT(tag|self[, where/index])
• DIRECT_TEXT(tag|self)
• ATTR(tag|self, attr[, where/index])
• FIRST_TEXT(...), LAST_TEXT(...)
• FIRST_ATTR(...), LAST_ATTR(...)
• INNER_HTML(tag|self[, depth|MAX_DEPTH])
• RAW_INNER_HTML(tag|self[, depth|MAX_DEPTH])

Schema construction

• FLATTEN_TEXT(tag[, depth])
• FLATTEN(tag[, depth]) (alias)
• PROJECT(tag) AS (alias: expr, ...)
• FLATTEN_EXTRACT(tag) (compat alias of PROJECT)

Expression helpers

• COALESCE(a, b, ...)
• CASE WHEN ... THEN ... [ELSE ...] END
• TRIM, LTRIM, RTRIM
• LOWER, UPPER
• REPLACE
• CONCAT
• SUBSTRING / SUBSTR
• LENGTH / CHAR_LENGTH
• POSITION(substr IN str) / LOCATE

Aggregation and analytics

• COUNT(tag|*)
• SUMMARIZE(*)
• TFIDF(...)

Source constructors

• RAW('<html...>')
• PARSE('<html...>')
• PARSE(SELECT inner_html(...) FROM doc ...)
• FRAGMENTS(...) (deprecated; prefer PARSE(...))

Behavior and constraints

• self refers to the current node for the current row produced by FROM.
• Inside axis scopes such as EXISTS(descendant WHERE ...), self is rebound to the node being evaluated in that scope.
• attr.foo is shorthand for attributes.foo in operand paths (including alias/axis-qualified forms).
• TEXT()/INNER_HTML()/RAW_INNER_HTML() require an outer WHERE clause.
• The outer WHERE must include a non-tag self predicate (for example attributes.*, parent.*, etc.), not only tag = ....
• INNER_HTML(tag) and RAW_INNER_HTML(tag) default to depth 1 when depth is omitted.
• INNER_HTML(tag, MAX_DEPTH) and RAW_INNER_HTML(tag, MAX_DEPTH) auto-expand to each row’s max_depth.
• In one SELECT, INNER_HTML/RAW_INNER_HTML depth mode must be consistent (do not mix default, numeric depth, and MAX_DEPTH).
• In one SELECT, do not mix INNER_HTML() and RAW_INNER_HTML() projections.