Reimplements identifier lookup to work over the AST

src/ast.c

@@ -1,5 +1,6 @@
 #include "ast.h"
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -989,3 +990,209 @@ char *TypeTagToString(TypeTag *tag)
     }
     }
 }
+
+void LinkParentPointers(Node *node)
+{
+    static Node *parent = NULL;
+
+    if (node == NULL)
+    {
+        fprintf(stderr, "wraith: Encountered NULL node while linking parent pointers.\n");
+        return;
+    }
+
+    node->parent = parent;
+    parent = node;
+    Recurse(node, *LinkParentPointers);
+}
+
+Node *GetIdFromStruct(Node *structDecl)
+{
+    if (structDecl->syntaxKind != StructDeclaration)
+    {
+        fprintf(stderr, "wraith: Attempted to call GetIdFromStruct on node with kind: %s.\n",
+                SyntaxKindString(structDecl->syntaxKind));
+        return NULL;
+    }
+
+    return structDecl->structDeclaration.identifier;
+}
+
+Node *GetIdFromFunction(Node *funcDecl) 
+{
+    if (funcDecl->syntaxKind != FunctionDeclaration)
+    {
+        fprintf(stderr, "wraith: Attempted to call GetIdFromFunction on node with kind: %s.\n",
+                SyntaxKindString(funcDecl->syntaxKind));
+        return NULL;
+    }
+
+    Node *sig = funcDecl->functionDeclaration.functionSignature;
+    return sig->functionSignature.identifier;
+}
+
+Node *GetIdFromDeclaration(Node *decl)
+{
+    if (decl->syntaxKind != Declaration)
+    {
+        fprintf(stderr, "wraith: Attempted to call GetIdFromDeclaration on node with kind: %s.\n",
+                SyntaxKindString(decl->syntaxKind));
+    }
+
+    return decl->declaration.identifier;
+}
+
+bool AssignmentHasDeclaration(Node *assign)
+{
+    return (assign->syntaxKind == Assignment 
+            && assign->assignmentStatement.left->syntaxKind == Declaration);
+}
+
+Node *GetIdFromAssignment(Node *assign)
+{
+    if (assign->syntaxKind != Assignment)
+    {
+        fprintf(stderr, "wraith: Attempted to call GetIdFromAssignment on node with kind: %s.\n",
+                SyntaxKindString(assign->syntaxKind));
+    }
+
+    if (AssignmentHasDeclaration(assign))
+    {
+        return GetIdFromDeclaration(assign->assignmentStatement.left);
+    }
+
+    return NULL;
+}
+
+bool NodeMayHaveId(Node *node)
+{
+    switch (node->syntaxKind)
+    {
+    case StructDeclaration:
+    case FunctionDeclaration:
+    case Declaration:
+    case Assignment:
+        return true;
+    default:
+        return false;
+    }
+}
+
+Node *TryGetId(Node *node)
+{
+    switch (node->syntaxKind)
+    {
+    case StructDeclaration:
+        return GetIdFromStruct(node);
+    case FunctionDeclaration:
+        return GetIdFromFunction(node);
+    case Declaration:
+        return GetIdFromDeclaration(node);
+    default:
+        return NULL;
+    }
+}
+
+Node *LookupFunctionArgId(Node *funcDecl, char *target)
+{
+    Node *args = 
+        funcDecl->functionDeclaration.functionSignature->functionSignature.arguments;
+
+    uint32_t i;
+    for (i = 0; i < args->functionArgumentSequence.count; i += 1)
+    {
+        Node *arg = args->functionArgumentSequence.sequence[i];
+        if (arg->syntaxKind != Declaration)
+        {
+            fprintf(stderr,
+                    "wraith: Encountered %s node in function signature args list.\n",
+                    SyntaxKindString(arg->syntaxKind));
+            continue;
+        }
+
+        Node *argId = GetIdFromDeclaration(arg);
+        if (argId != NULL && strcmp(target, argId->identifier.name) == 0)
+        { 
+            return argId;
+        }
+    }
+
+    return NULL;
+}
+
+Node *LookupIdNode(Node *current, Node *prev, char *target)
+{
+    if (current == NULL) return NULL;
+
+    /* If this node may have an identifier declaration inside it, attempt to look up the identifier
+     * node itself, returning it if it matches the given target name. */
+    if (NodeMayHaveId(current))
+    {
+        Node *candidateId = TryGetId(current);
+        if (candidateId != NULL && strcmp(target, candidateId->identifier.name) == 0)
+        {
+            return candidateId;
+        }
+
+        /* If the candidate node was not the one we wanted, but the current node is a function
+         * declaration, it's possible that the identifier we want is one of the function's 
+         * parameters rather than the function's name itself. */
+        if (current->syntaxKind == FunctionDeclaration)
+        {
+            Node *match = LookupFunctionArgId(current, target);
+            if (match != NULL) return match;
+        }
+    }
+
+    /* If this is the start of our search, we should not attempt to look at
+     * child nodes. Only looking up the AST is valid at this point.
+     *
+     * This has the notable side-effect that this function will return NULL if
+     * you attempt to look up a struct's internals starting from the node
+     * representing the struct itself. */
+    if (prev == NULL)
+    {
+        return LookupIdNode(current->parent, current, target);
+    }
+
+    uint32_t i;
+    uint32_t idxLimit;
+    switch (current->syntaxKind)
+    {
+    case DeclarationSequence:
+        for (i = 0; i < current->declarationSequence.count; i += 1)
+        {
+            Node *decl = current->declarationSequence.sequence[i];
+            Node *declId = TryGetId(decl);
+            if (declId != NULL) return declId;
+        }
+        break;
+    case StatementSequence:
+        idxLimit = current->statementSequence.count;
+        for (i = 0; i < current->statementSequence.count; i += 1)
+        {
+            if (current->statementSequence.sequence[i] == prev)
+            {
+                idxLimit = i;
+                break;
+            }
+        }
+
+        for (i = 0; i < idxLimit; i += 1)
+        {
+            Node *stmt = current->statementSequence.sequence[i];
+            if (stmt == prev) continue;
+
+            if (NodeMayHaveId(stmt))
+            {
+                Node *candidateId = TryGetId(current);
+                if (candidateId != NULL && strcmp(target, candidateId->identifier.name) == 0)
+                {
+                    return candidateId;
+                }
+            }
+        }
+        break;
+    }
+    return LookupIdNode(current->parent, current, target);
+}

src/ast.h

@@ -373,7 +373,10 @@ const char *SyntaxKindString(SyntaxKind syntaxKind);
  * function in all other cases. */
 void Recurse(Node *node, void (*func)(Node*));
 
+void LinkParentPointers(Node *node);
+
 TypeTag *MakeTypeTag(Node *node);
 char *TypeTagToString(TypeTag *tag);
 
+Node *LookupIdNode(Node *current, Node *prev, char *target);
 #endif /* WRAITH_AST_H */

src/identcheck.c

@@ -187,7 +187,7 @@ IdNode *MakeIdTree(Node *astNode, IdNode *parent)
     {
         char *name = astNode->identifier.name;
         mainNode = MakeIdNode(Placeholder, name, parent);
-        IdNode *lookupNode = LookupId(mainNode, NULL, name);
+        Node *lookupNode = LookupIdNode(astNode, NULL, name);
         if (lookupNode == NULL)
         {
             fprintf(stderr, "wraith: Could not find IdNode for id %s\n", name);

src/main.c

@@ -86,6 +86,7 @@ int main(int argc, char *argv[])
                 }
                 else
                 {
+                    LinkParentPointers(rootNode);
                     {
                         IdNode *idTree = MakeIdTree(rootNode, NULL);
                         printf("\n");