daScript/daslib/linq_fold_sql.das at master · feiyunwill/daScript · GitHub

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options gen2

options indenting = 4

options _comment_hygiene = true

module linq_fold_sql shared public

//! linq_fold SQL source pass-through: ``extract_sql_source``. Lets ``_fold`` over a

//! ``db |> select_from(type<Row>)`` chain (where ``Row`` is a ``[sql_table]``/``[sql_view]``/

//! ``[sql_fts5]`` struct) re-dispatch the whole chain to the ``_sql`` macro instead of folding the

//! materialized full-table ``array<Row>`` in memory. There is no emitting adapter — ``_sql`` is a

//! complete parallel lowering; this module only recognizes the source. Companion to

//! ``daslib/linq_fold``; provider-neutral (matches the ``[sql_table]`` annotation, not a runner

//! type), so it loads unconditionally. See daslib/linq_fold.md.

require daslib/linq_fold_common public

require daslib/ast_boost

require daslib/ast

// True iff `sql_linq` (which defines the `_sql` macro) is in the current program. A consumer may

// require a provider boost (for `select_from`) without `daslib/sql_linq`; then we must NOT rewrite

// to `_sql` (it wouldn't resolve) — `_fold` falls back to the in-memory array path instead.

[macro_function]

def sql_linq_loaded(prog : ProgramPtr) : bool {

var found = false

program_for_each_module(prog) $(mod) {

if (mod.name == "sql_linq") {

found = true

}

return found

}

def private is_sql_table_select(c : ExprCall?) : bool {

if (c._type == null || !c._type.isGoodArrayType || c._type.firstType == null) return false

let st = c._type.firstType.structType

if (st == null) return false

for (annDecl in st.annotations) {

if (annDecl.annotation.name == "sql_table" || annDecl.annotation.name == "sql_view"

|| annDecl.annotation.name == "sql_fts5") return true

}

return false

}

[macro_function]

def extract_sql_source(var expr : Expression?) : ExprCall? {

var e = expr

while (e != null && e is ExprCall) {

var c = e as ExprCall

if (get_call_short_name(c) == "select_from") {

return is_sql_table_select(c) ? c : null

}

if (empty(c.arguments)) break

e = c.arguments[0]

}

return null

}

daScript/daslib/linq_fold_sql.das at master · feiyunwill/daScript · GitHub

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