Lua Queries: make object attributes variables

common/space_lua/eval.ts

@@ -257,7 +257,7 @@ export function evalExpression(
         if (!findFromClause) {
           throw new LuaRuntimeError("No from clause found", sf.withCtx(e.ctx));
         }
-        const objectVariable = findFromClause.name || "_";
+        const objectVariable = findFromClause.name;
         const objectExpression = findFromClause.expression;
         return Promise.resolve(evalExpression(objectExpression, env, sf)).then(
           async (collection: LuaValue) => {

common/space_lua/query_collection.test.ts

@@ -124,11 +124,10 @@ Deno.test("ArrayQueryCollection", async () => {
   assertEquals(result8[2], "Jane Doe");
   assertEquals(result8[3], "Bob Johnson");
 
-  // Test select with native function
+  // Test select with native function and implicit object variable
   const result9 = await collection2.query(
     {
-      objectVariable: "p",
+      select: parseExpressionString("build_name(firstName, lastName)"),
-      select: parseExpressionString("build_name(p.firstName, p.lastName)"),
     },
     rootEnv,
     LuaStackFrame.lostFrame,

common/space_lua/query_collection.ts

@@ -1,12 +1,31 @@
 import type { LuaExpression } from "$common/space_lua/ast.ts";
-import { LuaEnv, type LuaStackFrame } from "$common/space_lua/runtime.ts";
+import {
+  LuaEnv,
+  luaGet,
+  luaKeys,
+  type LuaStackFrame,
+} from "$common/space_lua/runtime.ts";
 import { evalExpression } from "$common/space_lua/eval.ts";
 import { asyncQuickSort } from "$common/space_lua/util.ts";
 import type { DataStore } from "$lib/data/datastore.ts";
 
-function buildItemEnv(objectVariable: string, item: any, env: LuaEnv): LuaEnv {
+function buildItemEnv(
+  objectVariable: string | undefined,
+  item: any,
+  env: LuaEnv,
+  sf: LuaStackFrame,
+): LuaEnv {
   const itemEnv = new LuaEnv(env);
-  itemEnv.setLocal(objectVariable, item);
+  if (!objectVariable) {
+    // Inject all item keys as variables
+    for (const key of luaKeys(item)) {
+      itemEnv.setLocal(key, luaGet(item, key, sf));
+    }
+    // As well as _
+    itemEnv.setLocal("_", item);
+  } else {
+    itemEnv.setLocal(objectVariable, item);
+  }
   return itemEnv;
 }
 
@@ -19,7 +38,7 @@ export type LuaOrderBy = {
  * Represents a query for a collection
  */
 export type LuaCollectionQuery = {
-  objectVariable: string;
+  objectVariable?: string;
   // The filter expression evaluated with Lua
   where?: LuaExpression;
   // The order by expression evaluated with Lua
@@ -55,7 +74,7 @@ export class ArrayQueryCollection<T> implements LuaQueryCollection {
 
     // Filter the array
     for (const item of this.array) {
-      const itemEnv = buildItemEnv(query.objectVariable, item, env);
+      const itemEnv = buildItemEnv(query.objectVariable, item, env, sf);
       if (query.where && !await evalExpression(query.where, itemEnv, sf)) {
         continue;
       }
@@ -77,8 +96,8 @@ async function applyTransforms(
     result = await asyncQuickSort(result, async (a, b) => {
       // Compare each orderBy clause until we find a difference
       for (const { expr, desc } of query.orderBy!) {
-        const aEnv = buildItemEnv(query.objectVariable, a, env);
+        const aEnv = buildItemEnv(query.objectVariable, a, env, sf);
-        const bEnv = buildItemEnv(query.objectVariable, b, env);
+        const bEnv = buildItemEnv(query.objectVariable, b, env, sf);
 
         const aVal = await evalExpression(expr, aEnv, sf);
         const bVal = await evalExpression(expr, bEnv, sf);
@@ -99,7 +118,7 @@ async function applyTransforms(
   if (query.select) {
     const newResult = [];
     for (const item of result) {
-      const itemEnv = buildItemEnv(query.objectVariable, item, env);
+      const itemEnv = buildItemEnv(query.objectVariable, item, env, sf);
       newResult.push(await evalExpression(query.select, itemEnv, sf));
     }
     result = newResult;
@@ -134,7 +153,7 @@ export class DataStoreQueryCollection implements LuaQueryCollection {
     ) {
       // Enrich
       this.dataStore.enrichObject(value);
-      const itemEnv = buildItemEnv(query.objectVariable, value, env);
+      const itemEnv = buildItemEnv(query.objectVariable, value, env, sf);
       if (query.where && !await evalExpression(query.where, itemEnv, sf)) {
         continue;
       }

website/Space Lua.md

@@ -61,8 +61,8 @@ Space Lua has a feature called [[Space Lua/Lua Integrated Query]], which integra
 
 ${query[[
   from tag "page"
-  order by _.lastModified desc
+  order by lastModified desc
-  select _.name
+  select name
   limit 3
 ]]}
 

website/Space Lua/Lua Integrated Query.md

@@ -44,7 +44,7 @@ And the shorter:
 
     from <<expression>>
 
-implicitly binding each item to the variable `_`.
+implicitly binding each item to the variable `_` as well as making all attributes directly available as variables.
 
 Example without variable binding:
 ${query[[from {1, 2, 3} select _]]}
@@ -52,8 +52,8 @@ ${query[[from {1, 2, 3} select _]]}
 With variable binding:
 ${query[[from n = {1, 2, 3} select n]]}
 
-A more realist example using `tag`:
+A more realistic example using `tag`:
-${query[[from t = tag "page" limit 3 select t.name]]}
+${query[[from tag "page" order by lastModified select name limit 3]]}
 
 ## `where <expression>`
 The `where` clause allows you to filter data. When the expression evaluated to a truthy value, the item is included in the result.
@@ -64,7 +64,7 @@ ${query[[from {1, 2, 3, 4, 5} where _ > 2]]}
 
 Or to select all pages tagged with `#meta`:
 
-${query[[from tag "page" where table.includes(_.tags, "meta")]]}
+${query[[from tag "page" where table.includes(tags, "meta")]]}
 
 ## `order by <expression> [desc]`
 The `order by` clause allows you to sort data, when `desc` is specified it reverts the sort order.
@@ -72,8 +72,8 @@ The `order by` clause allows you to sort data, when `desc` is specified it rever
 As an example, the last 3 modified pages:
 ${query[[
   from tag "page"
-  order by _.lastModified desc
+  order by lastModified desc
-  select _.name
+  select name
   limit 3
 ]]}
 
@@ -101,10 +101,10 @@ ${query[[from tag "page" select _.name limit 3]]}
 
 You can also return tables or other complex values:
 ${query[[
-  from tag "page" 
+  from p = tag "page" 
   select {
-    name = _.name,
+    name = p.name,
-    modified = _.lastModified
+    modified = p.lastModified
   }
   limit 3
 ]]}