Alias as wire (#135)

* Tests and docs

* Syntax change

* Changeset

Author: aarne

.changeset/sharp-badgers-switch.md

@@ -0,0 +1,8 @@
+---
+"@stackables/bridge-compiler": minor
+"@stackables/bridge-parser": minor
+"@stackables/bridge-core": minor
+"@stackables/bridge": minor
+---
+
+New alias syntax alias name <- source.from ?? "full syntax" catch "supported"

README.md

@@ -82,7 +82,7 @@ The `.bridge` language is designed to be scannable.
 | **Null Coalesce** | `o.name <- i.name \|\| "N/A"`  | Alternative used if the current source resolves to `null`.                              |
 | **Error Guard**   | `o.price <- api.price catch 0` | Alternative used if the current source **throws** an exception.                         |
 | **Ternary**       | `o.val <- i.isPro ? a : b`     | Evaluates condition; strictly pulls only the chosen branch.                             |
-| **Node Alias**    | `alias uc:i.name as name`      | Evaluates an expression once and caches it as a local graph node.                       |
+| **Node Alias**    | `alias name <- uc:i.name`      | Evaluates an expression once and caches it as a local graph node.                       |
 | **Arrays**        | `o <- items[] as it { }`       | Iterates over an array, creating a local shadow scope for each element.                 |
 
 **[Read the Full Language Guide](https://bridge.sdk42.com/reference/10-core-concepts/)**

examples/without-graphql/should_i_go_outside.bridge

@@ -27,7 +27,7 @@ bridge Query.should_i_go_outside {
   g.q <- i.cityName
   g.format = "json"
 
-  alias first:g as f
+  alias f <- first:g
 
   w.latitude  <- f.lat
   w.longitude <- f.lon

packages/bridge-compiler/src/codegen.ts

@@ -3454,7 +3454,7 @@ class CodegenContext {
             return this.elementWireToExpr(w, elVar);
           }
         }
-        // Check if this is a pipe tool call (alias tool:source as name)
+        // Check if this is a pipe tool call (alias name <- tool:source)
         if (isPull(w) && w.pipe) {
           return this.elementWireToExpr(w, elVar);
         }

packages/bridge-compiler/test/codegen.test.ts

@@ -2021,7 +2021,7 @@ describe("AOT codegen: async array mapping", () => {
         with output as o
 
         o.items <- api.results[] as item {
-          alias enricher:item as e
+          alias e <- enricher:item
           .name <- item.name ?? continue
           .extra <- e.data
         }
@@ -2107,7 +2107,7 @@ describe("AOT codegen: async array mapping", () => {
         o <- api.groups[] as g {
           .label <- g.name
           .items <- g.items[] as sub {
-            alias enricher:sub as e
+            alias e <- enricher:sub
             .value <- e.data
           }
         }
@@ -2145,7 +2145,7 @@ describe("AOT codegen: async array mapping", () => {
         with output as o
 
         o.items <- api.results[] as item {
-          alias enricher:item as e
+          alias e <- enricher:item
           .name <- item.name ?? continue
           .extra <- e.data catch "n/a"
         }
@@ -2178,7 +2178,7 @@ describe("AOT codegen: async array mapping", () => {
 
         o.title <- api.title
         o.items <- api.items[] as item {
-          alias enricher:item as e
+          alias e <- enricher:item
           .name <- item.name ?? continue
           .extra <- e.data
         }
@@ -2279,7 +2279,7 @@ bridge Query.catalog {
   with output as o
 
   o <- src.items[] as it {
-    alias enrich:it as e
+    alias e <- enrich:it
     .id <- it.item_id
     .label <- e.name
   }

packages/bridge-core/test/traversal-manifest-locations.test.ts

@@ -43,7 +43,7 @@ describe("buildTraversalManifest source locations", () => {
       bridge Query.test {
         with input as i
         with output as o
-        alias i.empty.array.error catch i.empty.array.error as clean
+        alias clean <- i.empty.array.error catch i.empty.array.error
         o.message <- i.empty.array?.error ?? i.empty.array.error catch clean
       }
     `);

packages/bridge-parser/src/bridge-format.ts

@@ -1650,7 +1650,7 @@ function serializeBridgeBlock(bridge: Bridge): string {
       }
     }
 
-    // Emit block-scoped local bindings: alias <source> as <name>
+    // Emit block-scoped local bindings: alias <name> <- <source>
     for (const [alias, info] of localBindingsByAlias) {
       // Ternary alias in element scope
       if (info.ternaryWire) {
@@ -1679,7 +1679,7 @@ function serializeBridgeBlock(bridge: Bridge): string {
         const fallbackStr = serFallbacks(tw, sPipeOrRef);
         const errf = serCatch(tw, sPipeOrRef);
         lines.push(
-          `${indent}alias ${condStr} ? ${thenStr} : ${elseStr}${fallbackStr}${errf} as ${alias}`,
+          `${indent}alias ${alias} <- ${condStr} ? ${thenStr} : ${elseStr}${fallbackStr}${errf}`,
         );
         continue;
       }
@@ -1769,7 +1769,11 @@ function serializeBridgeBlock(bridge: Bridge): string {
           sourcePart = sRef(fromRef, true);
         }
       }
-      lines.push(`${indent}alias ${sourcePart} as ${alias}`);
+      const elemFb = serFallbacks(srcWire, sPipeOrRef);
+      const elemErrf = serCatch(srcWire, sPipeOrRef);
+      lines.push(
+        `${indent}alias ${alias} <- ${sourcePart}${elemFb}${elemErrf}`,
+      );
     }
 
     // Emit element-scoped tool declarations: with <tool> as <handle>
@@ -2219,7 +2223,7 @@ function serializeBridgeBlock(bridge: Bridge): string {
   }
 
   // ── Top-level alias declarations ─────────────────────────────────────
-  // Emit `alias <source> as <name>` for __local bindings that are NOT
+  // Emit `alias <name> <- <source>` for __local bindings that are NOT
   // element-scoped (those are handled inside serializeArrayElements).
   for (const [alias, info] of localBindingsByAlias) {
     // Ternary alias: emit `alias <cond> ? <then> : <else> [fallbacks] as <name>`
@@ -2237,7 +2241,7 @@ function serializeBridgeBlock(bridge: Bridge): string {
       const fallbackStr = serFallbacks(tw, sPipeOrRef);
       const errf = serCatch(tw, sPipeOrRef);
       lines.push(
-        `alias ${condStr} ? ${thenStr} : ${elseStr}${fallbackStr}${errf} as ${alias}`,
+        `alias ${alias} <- ${condStr} ? ${thenStr} : ${elseStr}${fallbackStr}${errf}`,
       );
       continue;
     }
@@ -2294,7 +2298,7 @@ function serializeBridgeBlock(bridge: Bridge): string {
     }
     const aliasFb = serFallbacks(srcWire, sPipeOrRef);
     const aliasErrf = serCatch(srcWire, sPipeOrRef);
-    lines.push(`alias ${sourcePart}${aliasFb}${aliasErrf} as ${alias}`);
+    lines.push(`alias ${alias} <- ${sourcePart}${aliasFb}${aliasErrf}`);
   }
   // Also emit wires reading from top-level __local bindings
   for (const lw of localReadWires) {