Merge pull request #223 from terminusdb/path_queries

Path queries

Author: Francesca-Bit

lib/query/woqlCore.js

@@ -709,9 +709,9 @@ function getClauseAndRemainder(pat) {
 
 function compilePredicate(pp, q) {
   if (pp.indexOf('<') !== -1 && pp.indexOf('>') !== -1) {
-    let pred = pp.slice(1, pp.length - 1);
+    const pred = pp.slice(1, pp.length - 1);
     // eslint-disable-next-line no-multi-assign,no-constant-condition
-    const cleaned = (pred = '*' ? 'owl:topObjectProperty' : q.cleanPathPredicate(pred));
+    const cleaned = pred === '.' ? null : q.cleanPathPredicate(pred);
     return {
       '@type': 'PathOr',
       or: [{
@@ -725,18 +725,15 @@ function compilePredicate(pp, q) {
     };
   } if (pp.indexOf('<') !== -1) {
     const pred = pp.slice(1, pp.length);
-    // let cleaned = pred === '*' ? 'owl:topObjectProperty' : q.cleanPathPredicate(pred)
-    const cleaned = q.cleanPathPredicate(pred);
+    const cleaned = pred === '.' ? null : q.cleanPathPredicate(pred);
     return { '@type': 'InversePathPredicate', predicate: cleaned };
   } if (pp.indexOf('>') !== -1) {
     const pred = pp.slice(0, pp.length - 1);
-    // let cleaned = pred === '*' ? 'owl:topObjectProperty' : q.cleanPathPredicate(pred)
-    const cleaned = q.cleanPathPredicate(pred);
+    const cleaned = pred === '.' ? null : q.cleanPathPredicate(pred);
     return { '@type': 'PathPredicate', predicate: cleaned };
   }
-  // let pred = pp === '*' ? 'owl:topObjectProperty' : q.cleanPathPredicate(pp)
-  const pred = q.cleanPathPredicate(pp);
-  return { '@type': 'PathPredicate', predicate: pred };
+  const cleaned = pp === '.' ? null : q.cleanPathPredicate(pp);
+  return { '@type': 'PathPredicate', predicate: cleaned };
 }
 
 /**
@@ -843,6 +840,8 @@ function copyJSON(orig, rollup) {
         }
       }
       nuj[k] = nupart;
+    } else if (part === null) {
+      // do nothing
     } else if (typeof part === 'object') {
       const q = copyJSON(part, rollup);
       if (!q || !UTILS.empty(q)) nuj[k] = q;

lib/query/woqlPrinter.js

@@ -357,9 +357,9 @@ WOQLPrinter.prototype.decompilePathPattern = function (pstruct) {
   // eslint-disable-next-line default-case
   switch (t) {
     case 'InversePathPredicate':
-      return `<${pstruct.predicate}`;
+      return pstruct.predicate ? `<${pstruct.predicate}` : '<.';
     case 'PathPredicate':
-      return pstruct.predicate;
+      return pstruct.predicate ? `${pstruct.predicate}` : '.';
     case 'PathPlus':
       var next = pstruct.plus;
       if (Array.isArray(next)) next = next[0];

test/woqlPathquery.js

@@ -27,6 +27,38 @@ describe('woql path query and path query prettyprint', () => {
     expect(query.prettyPrint()).to.eql('WOQL.path("v:X", "hop", "v:Y", "v:Path")');
   });
 
+  it('simple any path query', () => {
+    const query = WOQL.path('v:X', '.*,name', 'v:Y');
+    const json = {
+      '@type': 'Path',
+      subject: {
+        '@type': 'NodeValue',
+        variable: 'X',
+      },
+      pattern: {
+        '@type': "PathSequence",
+        'sequence': [
+          {
+            '@type': "PathStar",
+            'star': {
+              '@type': "PathPredicate"
+            }
+          },
+          {
+            '@type': "PathPredicate",
+            'predicate' : "name"
+          }
+        ]
+      },
+      object: {
+        '@type': 'Value',
+        variable: 'Y',
+      }
+    };
+    expect(query.json()).to.eql(json);
+    expect(query.prettyPrint()).to.eql('WOQL.path("v:X", "(.*),name", "v:Y")');
+  });
+
   it('test plus directed path query', () => {
     const query = WOQL.path('v:X', '<hop+', 'v:Y', 'v:Path');
     const json = {