small code improvements

prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/pbs/PbsFrontendCompiler.java

@@ -1,6 +1,7 @@
 package p.studio.compiler.pbs;
 
 import p.studio.compiler.models.IRFunction;
+import p.studio.compiler.models.IRBackendFile;
 import p.studio.compiler.pbs.ast.PbsAst;
 import p.studio.compiler.pbs.lexer.PbsLexer;
 import p.studio.compiler.pbs.parser.PbsParser;
@@ -13,14 +14,14 @@ import java.util.HashSet;
 import java.util.Set;
 
 public final class PbsFrontendCompiler {
-    public ReadOnlyList<IRFunction> compileFile(
+    public IRBackendFile compileFile(
             final FileId fileId,
             final String source,
             final DiagnosticSink diagnostics) {
         final var tokens = PbsLexer.lex(source, fileId, diagnostics);
         final var ast = PbsParser.parse(tokens, fileId, diagnostics);
         validateFunctionNames(ast, diagnostics);
-        return lowerFunctions(fileId, ast);
+        return new IRBackendFile(fileId, lowerFunctions(fileId, ast));
     }
 
     private void validateFunctionNames(

prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/pbs/ast/PbsAst.java

@@ -4,10 +4,6 @@ import p.studio.compiler.source.Span;
 import p.studio.utilities.structures.ReadOnlyList;
 
 public final class PbsAst {
-    public sealed interface Statement permits LetStatement, ReturnStatement, ExpressionStatement {
-        Span span();
-    }
-
     private PbsAst() {
     }
 
@@ -36,6 +32,10 @@ public final class PbsAst {
             Span span) {
     }
 
+    public sealed interface Statement permits LetStatement, ReturnStatement, ExpressionStatement {
+        Span span();
+    }
+
     public record Block(
             ReadOnlyList<Statement> statements,
             Span span) {

prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/services/PBSFrontendPhaseService.java

@@ -4,11 +4,9 @@ import lombok.extern.slf4j.Slf4j;
 import p.studio.compiler.messages.BuildingIssueSink;
 import p.studio.compiler.messages.FrontendPhaseContext;
 import p.studio.compiler.models.IRBackend;
-import p.studio.compiler.models.IRFunction;
 import p.studio.compiler.pbs.PbsFrontendCompiler;
 import p.studio.compiler.source.diagnostics.DiagnosticSink;
 import p.studio.utilities.logs.LogAggregator;
-import p.studio.utilities.structures.MutableList;
 
 @Slf4j
 public class PBSFrontendPhaseService implements FrontendPhaseService {
@@ -20,7 +18,7 @@ public class PBSFrontendPhaseService implements FrontendPhaseService {
             final DiagnosticSink diagnostics,
             final LogAggregator logs,
             final BuildingIssueSink issues) {
-        final MutableList<IRFunction> functions = MutableList.create();
+        final var irBackendAggregator = IRBackend.aggregator();
 
         for (final var pId : ctx.stack.reverseTopologicalOrder) {
             final var fileIds = ctx.fileTable.getFiles(pId);
@@ -30,10 +28,11 @@ public class PBSFrontendPhaseService implements FrontendPhaseService {
                 switch (sourceHandle.getExtension()) {
                     case "pbs": {
                         sourceHandle.readUtf8().ifPresentOrElse(
-                                utf8Content -> functions.addAll(frontendCompiler
+                                utf8Content -> {
-                                        .compileFile(fId, utf8Content, diagnostics)
+                                    final var irBackendFile = frontendCompiler
-                                        .stream()
+                                            .compileFile(fId, utf8Content, diagnostics);
-                                        .toList()),
+                                    irBackendAggregator.merge(irBackendFile);
+                                },
                                 () -> issues.report(builder -> builder
                                         .error(true)
                                         .message("Failed to read file content: %s".formatted(sourceHandle.toString()))));
@@ -45,10 +44,8 @@ public class PBSFrontendPhaseService implements FrontendPhaseService {
             }
         }
 
-        logs.using(log).debug("PBS frontend lowered %d function(s) to IR".formatted(functions.size()));
+        final var irBackend = irBackendAggregator.emit();
-        return IRBackend
+        logs.using(log).debug("PBS frontend lowered to IR BE:\n%s".formatted(irBackend));
-                .builder()
+        return irBackend;
-                .functions(functions.toReadOnlyList())
-                .build();
     }
 }

prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/pbs/PbsFrontendCompilerTest.java

@@ -23,7 +23,8 @@ class PbsFrontendCompilerTest {
 
         final var diagnostics = DiagnosticSink.empty();
         final var compiler = new PbsFrontendCompiler();
-        final var functions = compiler.compileFile(new FileId(0), source, diagnostics);
+        final var fileBackend = compiler.compileFile(new FileId(0), source, diagnostics);
+        final var functions = fileBackend.functions();
 
         assertTrue(diagnostics.isEmpty(), "Valid program should not report diagnostics");
         assertEquals(2, functions.size());

prometeu-compiler/prometeu-build-pipeline/src/main/java/p/studio/compiler/workspaces/stages/FrontendPhasePipelineStage.java

@@ -27,7 +27,6 @@ public class FrontendPhasePipelineStage implements PipelineStage {
         final var diagnostics = DiagnosticSink.empty();
         final var issues = BuildingIssueSink.empty();
         ctx.irBackend = service.get().compile(frontendPhaseContext, diagnostics, logs, issues);
-        logs.using(log).debug("IR Backend: " + ctx.irBackend);
         logs.using(log).debug("Frontend phase completed successfully!");
         adaptDiagnostics(diagnostics, issues);
         return issues;

prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackend.java

@@ -2,6 +2,7 @@ package p.studio.compiler.models;
 
 import lombok.Builder;
 import lombok.Getter;
+import p.studio.utilities.structures.MutableList;
 import p.studio.utilities.structures.ReadOnlyList;
 
 @Builder
@@ -10,9 +11,28 @@ public class IRBackend {
     @Builder.Default
     private final ReadOnlyList<IRFunction> functions = ReadOnlyList.empty();
 
-    /**
+    public static IRBackendAggregator aggregator() {
-     * Returns a stable human-readable representation useful for debug logs and tests.
+        return new IRBackendAggregator();
-     */
+    }
+
+    public static final class IRBackendAggregator {
+        private final MutableList<IRFunction> functions = MutableList.create();
+
+        public void merge(final IRBackendFile backendFile) {
+            if (backendFile == null) {
+                return;
+            }
+            functions.addAll(backendFile.functions());
+        }
+
+        public IRBackend emit() {
+            return IRBackend
+                    .builder()
+                    .functions(functions.toReadOnlyList())
+                    .build();
+        }
+    }
+
     @Override
     public String toString() {
         final var sb = new StringBuilder();

prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackendFile.java

@@ -0,0 +1,19 @@
+package p.studio.compiler.models;
+
+import p.studio.compiler.source.identifiers.FileId;
+import p.studio.utilities.structures.ReadOnlyList;
+
+import java.util.Objects;
+
+public record IRBackendFile(
+        FileId fileId,
+        ReadOnlyList<IRFunction> functions) {
+    public IRBackendFile {
+        fileId = Objects.requireNonNull(fileId, "fileId");
+        functions = functions == null ? ReadOnlyList.empty() : functions;
+    }
+
+    public static IRBackendFile empty(final FileId fileId) {
+        return new IRBackendFile(fileId, ReadOnlyList.empty());
+    }
+}

prometeu-infra/src/main/java/p/studio/utilities/structures/MutableList.java

@@ -1,10 +1,6 @@
 package p.studio.utilities.structures;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collection;
-import java.util.List;
-import java.util.ListIterator;
-import java.util.Objects;
 import java.util.stream.Stream;
 
 public interface MutableList<T> extends ReadOnlyCollection<T>, List<T> {
@@ -114,6 +110,17 @@ public interface MutableList<T> extends ReadOnlyCollection<T>, List<T> {
         return asList().containsAll(c);
     }
 
+    /**
+     * Appends all functions from the given file using, similar to
+     * {@link java.util.List#addAll(java.util.Collection)} semantics.
+     */
+    default boolean addAll(final ReadOnlyCollection<? extends T> c) {
+        if (ReadOnlyCollection.isEmpty(c)) {
+            return false;
+        }
+        return asList().addAll(c.asCollection());
+    }
+
     @Override
     default boolean addAll(final Collection<? extends T> c) {
         return asList().addAll(c);