[LIQ] Unify from, select, and group by clauses to use field lists, implement multi-source cross-join (#1909)

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* Website: Make manual build ref configurable

* [LIQ] Unify `from`, `select`, and `group by` clauses to use field lists

Query clauses `from`, `select`, and `group by` now accept the same field
syntax as Lua table constructors (`name = expr`, bare expr, or `[expr]
= expr`), giving them a consistent grammar and enabling named bindings
everywhere. #feature

What changed:

* New `FieldList` rule in `lua.grammar`. All three clauses now parse
  their arguments through it instead of using expression lists or the
  special `Name "=" exp` pattern.

* AST types `LuaFromClause`, `LuaSelectClause`, and `LuaGroupByClause`
  now carry fields: `LuaTableField[]` instead of a single expression or
  an expression array. The parser, static analysis helpers and the
  evaluator are all updated to work with this new shape.

Named bindings in `select`
--------------------------
`select name, age` now derives column names from bare variable or
property access expressions so the result table has string keys (`name`,
`age`) rather than integer indices. Explicit naming still works.

Named bindings in `group by`
----------------------------
`group b`y fields can carry explicit aliases that propagate into the
post-grouping scope. For example:

```sql
group by
  n = name
select {
  label = n
}
```

The alias `n` is now visible in `select`, `having`, and `order by`.
Previously only the raw expression form (`name`) was bound and an
explicit alias was silently lost. #bugfix

A new `LuaGroupByEntry` type pairs each `group by` expression with its
optional alias. The environment builder binds every
declared alias to the corresponding key value, regardless of whether the
group key is a scalar or a multi-key table.

Named bindings in `from`
------------------------
`from p = page` continues to work as before. The clause now also accepts
the full field-list syntax which lays the groundwork for multi-source
from (cross join) in a future change. #todo #feature

Complete LIQ syntax now
-----------------------
Complete LIQ syntax (in Postgres documentation style) could be now
roughly expressed as follows: #todo #documentation

```text
query[[ clause [...] ]]

where clause is one of:

    FROM field [, ...]
    WHERE condition
    GROUP BY field [, ...]
    HAVING condition
    SELECT field [, ...]
    ORDER BY sort_key [, ...]
    LIMIT count [, offset]
    OFFSET start

where field is one of:

    expression
    name = expression
    [expression] = expression

where sort_key is:

    expression [ ASC | DESC ]
               [ NULLS { FIRST | LAST } ]
               [ USING name ]
               [ USING FUNCTION function_body ]

where expression is any valid Lua expression, including:

    aggregate_call
    aggregate_call FILTER ( WHERE condition )
```

Signed-off-by: Matouš Jan Fialka <mjf@mjf.cz>

* Fix type error caused by earlier merge conflict resolution

Signed-off-by: Matouš Jan Fialka <mjf@mjf.cz>

* [LIQ] Cross-join support for multi-source `from`

Examples of what works now:

```
${query [[
  from
    x = {   1,   2 },
    y = {  10,  20 },
    z = { 100, 200 }
  select {
    sum = x + y + z
  }
]]}
```

Or (more complicated three-way cross-join) to illustrate:

```
${query [[
  from
    s = {
      { id = 1, name = 'Eva',  },
      { id = 2, name = 'Adam', },
      { id = 3, name = 'John', },
      { id = 4, name = 'Zef',  },
    },
    c = {
      { id = 101, title = 'Mathematics',      },
      { id = 102, title = 'Arts',             },
      { id = 103, title = 'Physics',          },
      { id = 104, title = 'Computer Science', },
      { id = 105, title = 'Literature',       },
    },
    e = {
      { sid = 1, cid = 101, },
      { sid = 1, cid = 103, },
      { sid = 2, cid = 101, },
      { sid = 2, cid = 102, },
      { sid = 2, cid = 103, },
      { sid = 3, cid = 102, },
      { sid = 3, cid = 105, },
      { sid = 4, cid = 101, },
      { sid = 4, cid = 103, },
      { sid = 4, cid = 104, },
    }
  where
    s.id  == e.sid and
    e.cid == c.id
  order by
    s.name
  group by
    s.name
  having
    s.name:match('^A') or
    s.name:match('f$')
  select
    student = s.name:upper(),
    courses = string_agg(c.title, ', '
      order by c.title desc
    )
]]}
```

Signed-off-by: Matouš Jan Fialka <mjf@mjf.cz>

---------

Signed-off-by: Matouš Jan Fialka <mjf@mjf.cz>
Co-authored-by: Zef Hemel <zef@zef.me>

...

This commit is contained in:

Matouš Jan Fialka

2026-03-25 14:48:57 +01:00

committed by GitHub

co-authored by Zef Hemel

parent 80cc5605da

commit 5996e51c6f

8 changed files with 515 additions and 229 deletions

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