Update Liquid Implementation

org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/LiquidRenderer.java

@@ -61,7 +61,7 @@ public class LiquidRenderer extends ResourceRenderer {
     XhtmlNode xn;
     try {
       LiquidDocument doc = engine.parse(liquidTemplate, "template");
-      String html = "rto do"; // engine.evaluate(doc, r, rcontext);
+      String html = engine.evaluate(doc, r.getBase(), rcontext);
       xn = new XhtmlParser().parseFragment(html);
       if (!x.getName().equals("div"))
         throw new FHIRException("Error in template: Root element is not 'div'");

org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/utils/BaseWrappers.java

@@ -42,6 +42,7 @@ public class BaseWrappers {
     public List<ResourceWrapper> getContained();
     public String getId();
     public XhtmlNode getNarrative() throws FHIRFormatError, IOException, FHIRException;
+    public Base getBase();
     public String getName();
     public void describe(XhtmlNode x) throws UnsupportedEncodingException, IOException;
     public void injectNarrative(XhtmlNode x, NarrativeStatus status) throws IOException;

org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/utils/DOMWrappers.java

@@ -307,6 +307,11 @@ public class DOMWrappers {
     public StructureDefinition getDefinition() {
       return definition;
     }
+
+    @Override
+    public Base getBase() {
+      throw new Error("Not Implemented yet");
+    }
   }
 
 }

org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/utils/DirectWrappers.java

@@ -214,6 +214,11 @@ public class DirectWrappers {
     public StructureDefinition getDefinition() {
       return context.getWorker().fetchTypeDefinition(wrapped.fhirType());
     }
+
+    @Override
+    public Base getBase() {
+      return wrapped;
+    }
   }
 
 }

org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/utils/ElementWrappers.java

@@ -214,6 +214,11 @@ public class ElementWrappers {
     public StructureDefinition getDefinition() {
       return definition;
     }
+
+    @Override
+    public Base getBase() {
+      return wrapped;
+    }
   }
 
   public static class PropertyWrapperMetaElement extends RendererWrapperImpl implements PropertyWrapper {

org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/LiquidEngine.java

@@ -1,39 +1,39 @@
 package org.hl7.fhir.r5.utils;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
-/*
+/*
-  Copyright (c) 2011+, HL7, Inc.
+  Copyright (c) 2011+, HL7, Inc.
-  All rights reserved.
+  All rights reserved.
-  
+  
-  Redistribution and use in source and binary forms, with or without modification, 
+  Redistribution and use in source and binary forms, with or without modification, 
-  are permitted provided that the following conditions are met:
+  are permitted provided that the following conditions are met:
-    
+    
-   * Redistributions of source code must retain the above copyright notice, this 
+   * Redistributions of source code must retain the above copyright notice, this 
-     list of conditions and the following disclaimer.
+     list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above copyright notice, 
+   * Redistributions in binary form must reproduce the above copyright notice, 
-     this list of conditions and the following disclaimer in the documentation 
+     this list of conditions and the following disclaimer in the documentation 
-     and/or other materials provided with the distribution.
+     and/or other materials provided with the distribution.
-   * Neither the name of HL7 nor the names of its contributors may be used to 
+   * Neither the name of HL7 nor the names of its contributors may be used to 
-     endorse or promote products derived from this software without specific 
+     endorse or promote products derived from this software without specific 
-     prior written permission.
+     prior written permission.
-  
+  
-  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
-  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
-  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
-  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
-  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
-  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
-  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
-  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
-  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
-  POSSIBILITY OF SUCH DAMAGE.
+  POSSIBILITY OF SUCH DAMAGE.
-  
+  
- */
+ */
-
 
 import org.hl7.fhir.exceptions.FHIRException;
 import org.hl7.fhir.exceptions.PathEngineException;
@@ -55,10 +55,10 @@ public class LiquidEngine implements IEvaluationContext {
   public interface ILiquidEngineIcludeResolver {
     public String fetchInclude(LiquidEngine engine, String name);
   }
-  
+
   private IEvaluationContext externalHostServices;
   private FHIRPathEngine engine;
-  private ILiquidEngineIcludeResolver includeResolver; 
+  private ILiquidEngineIcludeResolver includeResolver;
 
   private class LiquidEngineContext {
     private Object externalContext;
@@ -82,7 +82,7 @@ public class LiquidEngine implements IEvaluationContext {
     engine = new FHIRPathEngine(context);
     engine.setHostServices(this);
   }
-  
+
   public ILiquidEngineIcludeResolver getIncludeResolver() {
     return includeResolver;
   }
@@ -95,7 +95,7 @@ public class LiquidEngine implements IEvaluationContext {
     return new LiquidParser(source).parse(sourceName);
   }
 
-  public String evaluate(LiquidDocument document, Resource resource, Object appContext) throws FHIRException {
+  public String evaluate(LiquidDocument document, Base resource, Object appContext) throws FHIRException {
     StringBuilder b = new StringBuilder();
     LiquidEngineContext ctxt = new LiquidEngineContext(appContext);
     for (LiquidNode n : document.body) {
@@ -105,9 +105,10 @@ public class LiquidEngine implements IEvaluationContext {
   }
 
   private abstract class LiquidNode {
-    protected void closeUp() {}
+    protected void closeUp() {
+    }
 
-    public abstract void evaluate(StringBuilder b, Resource resource, LiquidEngineContext ctxt) throws FHIRException;
+    public abstract void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException;
   }
 
   private class LiquidConstant extends LiquidNode {
@@ -125,7 +126,7 @@ public class LiquidEngine implements IEvaluationContext {
     }
 
     @Override
-    public void evaluate(StringBuilder b, Resource resource, LiquidEngineContext ctxt) {
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) {
       b.append(constant);
     }
   }
@@ -135,48 +136,191 @@ public class LiquidEngine implements IEvaluationContext {
     private ExpressionNode compiled;
 
     @Override
-    public void evaluate(StringBuilder b, Resource resource, LiquidEngineContext ctxt) throws FHIRException {
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException {
       if (compiled == null)
         compiled = engine.parse(statement);
       b.append(engine.evaluateToString(ctxt, resource, resource, resource, compiled));
     }
   }
 
+  private class LiquidElsIf extends LiquidNode {
+    private String condition;
+    private ExpressionNode compiled;
+    private List<LiquidNode> body = new ArrayList<>();
+
+    @Override
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException {
+      for (LiquidNode n : body) {
+        n.evaluate(b, resource, ctxt);
+      }
+    }
+  }
+
   private class LiquidIf extends LiquidNode {
     private String condition;
     private ExpressionNode compiled;
     private List<LiquidNode> thenBody = new ArrayList<>();
+    private List<LiquidElsIf> elseIf = new ArrayList<>();
     private List<LiquidNode> elseBody = new ArrayList<>();
 
     @Override
-    public void evaluate(StringBuilder b, Resource resource, LiquidEngineContext ctxt) throws FHIRException {
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException {
       if (compiled == null)
         compiled = engine.parse(condition);
-      boolean ok = engine.evaluateToBoolean(ctxt, resource, resource, resource, compiled); 
+      boolean ok = engine.evaluateToBoolean(ctxt, resource, resource, resource, compiled);
-      List<LiquidNode> list = ok ? thenBody : elseBody;
+      List<LiquidNode> list = null;
+      if (ok) {
+        list = thenBody;
+
+      } else {
+        list = elseBody;
+        for (LiquidElsIf i : elseIf) {
+          if (i.compiled == null)
+            i.compiled = engine.parse(i.condition);
+          ok = engine.evaluateToBoolean(ctxt, resource, resource, resource, i.compiled);
+          if (ok) {
+            list = i.body;
+            break;
+          }
+        }
+      }
       for (LiquidNode n : list) {
         n.evaluate(b, resource, ctxt);
       }
     }
   }
 
-  private class LiquidLoop extends LiquidNode {
+  private class LiquidContinueExecuted extends FHIRException {
+    private static final long serialVersionUID = 4748737094188943721L;
+  }
+
+  private class LiquidContinue extends LiquidNode {
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException {
+      throw new LiquidContinueExecuted();
+    }
+  }
+
+  private class LiquidBreakExecuted extends FHIRException {
+    private static final long serialVersionUID = 6328496371172871082L;
+  }
+
+  private class LiquidBreak extends LiquidNode {
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException {
+      throw new LiquidBreakExecuted();
+    }
+  }
+
+  private class LiquidCycle extends LiquidNode {
+    private List<String> list = new ArrayList<>();
+    private int cursor = 0;
+
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException {
+      b.append(list.get(cursor));
+      cursor++;
+      if (cursor == list.size()) {
+        cursor = 0;
+      }
+    }
+  }
+
+  private class LiquidFor extends LiquidNode {
     private String varName;
     private String condition;
     private ExpressionNode compiled;
+    private boolean reversed = false;
+    private int limit = -1;
+    private int offset = -1;
     private List<LiquidNode> body = new ArrayList<>();
+    private List<LiquidNode> elseBody = new ArrayList<>();
+
     @Override
-    public void evaluate(StringBuilder b, Resource resource, LiquidEngineContext ctxt) throws FHIRException {
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException {
-      if (compiled == null)
+      if (compiled == null) {
-        compiled = engine.parse(condition);
+        ExpressionNodeWithOffset po = engine.parsePartial(condition, 0);
-      List<Base> list = engine.evaluate(ctxt, resource, resource, resource, compiled);
+        compiled = po.getNode();
-      LiquidEngineContext lctxt = new LiquidEngineContext(ctxt);
+        if (po.getOffset() < condition.length()) {
-      for (Base o : list) {
+          parseModifiers(condition.substring(po.getOffset()));
-        lctxt.vars.put(varName, o);
-        for (LiquidNode n : body) {
-          n.evaluate(b, resource, lctxt);
         }
       }
+      List<Base> list = engine.evaluate(ctxt, resource, resource, resource, compiled);
+      LiquidEngineContext lctxt = new LiquidEngineContext(ctxt);
+      if (list.isEmpty()) {
+        for (LiquidNode n : elseBody) {
+          n.evaluate(b, resource, lctxt);
+        }
+      } else {
+        if (reversed) {
+          Collections.reverse(list);
+        }
+        int i = 0;
+        for (Base o : list) {
+          if (offset >= 0 && i < offset) {
+            i++;
+            continue;
+          }
+          if (limit >= 0 && i == limit) {
+            break;
+          }          
+          lctxt.vars.put(varName, o);
+          boolean wantBreak = false;
+          for (LiquidNode n : body) {
+            try {
+              n.evaluate(b, resource, lctxt);
+            } catch (LiquidContinueExecuted e) {
+              break;
+            } catch (LiquidBreakExecuted e) {
+              wantBreak = true;
+              break;
+            }
+          }
+          if (wantBreak) {
+            break;
+          }
+          i++;
+        }
+      }
+    }
+
+    private void parseModifiers(String cnt) {
+      String src = cnt;
+      while (!Utilities.noString(cnt)) {
+        if (cnt.startsWith("reversed")) {
+          reversed = true;
+          cnt = cnt.substring(8);
+        } else if (cnt.startsWith("limit")) {
+          cnt = cnt.substring(5).trim();
+          if (!cnt.startsWith(":")) {
+            throw new FHIRException("Exception evaluating "+src+": limit is not followed by ':'");
+          }
+          cnt = cnt.substring(1).trim();
+          int i = 0;
+          while (i < cnt.length() && Character.isDigit(cnt.charAt(i))) {
+            i++;
+          }
+          if (i == 0) {
+            throw new FHIRException("Exception evaluating "+src+": limit is not followed by a number");
+          }
+          limit = Integer.parseInt(cnt.substring(0, i));
+          cnt = cnt.substring(i);
+        } else if (cnt.startsWith("offset")) {
+          cnt = cnt.substring(6).trim();
+          if (!cnt.startsWith(":")) {
+            throw new FHIRException("Exception evaluating "+src+": limit is not followed by ':'");
+          }
+          cnt = cnt.substring(1).trim();
+          int i = 0;
+          while (i < cnt.length() && Character.isDigit(cnt.charAt(i))) {
+            i++;
+          }
+          if (i == 0) {
+            throw new FHIRException("Exception evaluating "+src+": limit is not followed by a number");
+          }
+          offset = Integer.parseInt(cnt.substring(0, i));
+          cnt = cnt.substring(i);
+        } else {
+          throw new FHIRException("Exception evaluating "+src+": unexpected content at "+cnt);
+        }
+      }      
     }
   }
 
@@ -185,11 +329,11 @@ public class LiquidEngine implements IEvaluationContext {
     private Map<String, ExpressionNode> params = new HashMap<>();
 
     @Override
-    public void evaluate(StringBuilder b, Resource resource, LiquidEngineContext ctxt) throws FHIRException {
+    public void evaluate(StringBuilder b, Base resource, LiquidEngineContext ctxt) throws FHIRException {
       String src = includeResolver.fetchInclude(LiquidEngine.this, page);
       LiquidParser parser = new LiquidParser(src);
       LiquidDocument doc = parser.parse(page);
-      LiquidEngineContext nctxt =  new LiquidEngineContext(ctxt.externalContext);
+      LiquidEngineContext nctxt = new LiquidEngineContext(ctxt.externalContext);
       Tuple incl = new Tuple();
       nctxt.vars.put("include", incl);
       for (String s : params.keySet()) {
@@ -201,7 +345,7 @@ public class LiquidEngine implements IEvaluationContext {
     }
   }
 
-  public static class LiquidDocument  {
+  public static class LiquidDocument {
     private List<LiquidNode> body = new ArrayList<>();
 
   }
@@ -225,64 +369,124 @@ public class LiquidEngine implements IEvaluationContext {
     }
 
     private char next2() {
-      if (cursor >= source.length()-1)
+      if (cursor >= source.length() - 1)
         return 0;
       else
-        return source.charAt(cursor+1);
+        return source.charAt(cursor + 1);
     }
 
     private char grab() {
       cursor++;
-      return source.charAt(cursor-1);
+      return source.charAt(cursor - 1);
     }
 
     public LiquidDocument parse(String name) throws FHIRException {
       this.name = name;
       LiquidDocument doc = new LiquidDocument();
-      parseList(doc.body, new String[0]);
+      parseList(doc.body, false, new String[0]);
       return doc;
     }
 
-    private String parseList(List<LiquidNode> list, String[] terminators) throws FHIRException {
+    public LiquidCycle parseCycle(String cnt) {
+      LiquidCycle res = new LiquidCycle();
+      cnt = "," + cnt.substring(5).trim();
+      while (!Utilities.noString(cnt)) {
+        if (!cnt.startsWith(",")) {
+          throw new FHIRException("Script " + name + ": Script " + name + ": Found " + cnt.charAt(0) + " expecting ',' parsing cycle");
+        }
+        cnt = cnt.substring(1).trim();
+        if (!cnt.startsWith("\"")) {
+          throw new FHIRException("Script " + name + ": Script " + name + ": Found " + cnt.charAt(0) + " expecting '\"' parsing cycle");
+        }
+        cnt = cnt.substring(1);
+        int i = 0;
+        while (i < cnt.length() && cnt.charAt(i) != '"') {
+          i++;
+        }
+        if (i == cnt.length()) {
+          throw new FHIRException("Script " + name + ": Script " + name + ": Found unterminated string parsing cycle");
+        }
+        res.list.add(cnt.substring(0, i));
+        cnt = cnt.substring(i + 1).trim();
+      }
+      return res;
+    }
+
+    private String parseList(List<LiquidNode> list, boolean inLoop, String[] terminators) throws FHIRException {
       String close = null;
       while (cursor < source.length()) {
-        if (next1() == '{' && (next2() == '%' || next2() == '{' )) {
+        if (next1() == '{' && (next2() == '%' || next2() == '{')) {
-          if (next2() == '%') { 
+          if (next2() == '%') {
             String cnt = parseTag('%');
-            if (Utilities.existsInList(cnt, terminators)) {
+            if (isTerminator(cnt, terminators)) {
               close = cnt;
               break;
             } else if (cnt.startsWith("if "))
-              list.add(parseIf(cnt));
+              list.add(parseIf(cnt, inLoop));
-            else if (cnt.startsWith("loop "))
+            else if (cnt.startsWith("loop ")) // loop is deprecated, but still
+                                              // supported
               list.add(parseLoop(cnt.substring(4).trim()));
+            else if (cnt.startsWith("for "))
+              list.add(parseFor(cnt.substring(3).trim()));
+            else if (inLoop && cnt.equals("continue"))
+              list.add(new LiquidContinue());
+            else if (inLoop && cnt.equals("break"))
+              list.add(new LiquidBreak());
+            else if (inLoop && cnt.startsWith("cycle "))
+              list.add(parseCycle(cnt));
             else if (cnt.startsWith("include "))
               list.add(parseInclude(cnt.substring(7).trim()));
             else
-              throw new FHIRException("Script "+name+": Script "+name+": Unknown flow control statement "+cnt);
+              throw new FHIRException("Script " + name + ": Script " + name + ": Unknown flow control statement " + cnt);
           } else { // next2() == '{'
             list.add(parseStatement());
           }
         } else {
-          if (list.size() == 0 || !(list.get(list.size()-1) instanceof LiquidConstant))
+          if (list.size() == 0 || !(list.get(list.size() - 1) instanceof LiquidConstant))
             list.add(new LiquidConstant());
-          ((LiquidConstant) list.get(list.size()-1)).addChar(grab());
+          ((LiquidConstant) list.get(list.size() - 1)).addChar(grab());
         }
       }
       for (LiquidNode n : list)
         n.closeUp();
       if (terminators.length > 0)
-        if (!Utilities.existsInList(close, terminators))
+        if (!isTerminator(close, terminators))
-          throw new FHIRException("Script "+name+": Script "+name+": Found end of script looking for "+terminators);
+          throw new FHIRException("Script " + name + ": Script " + name + ": Found end of script looking for " + terminators);
       return close;
     }
 
-    private LiquidNode parseIf(String cnt) throws FHIRException {
+    private boolean isTerminator(String cnt, String[] terminators) {
+      if (Utilities.noString(cnt)) {
+        return false;
+      }
+      for (String t : terminators) {
+        if (t.endsWith(" ")) {
+          if (cnt.startsWith(t)) {
+            return true;
+          }
+        } else {
+          if (cnt.equals(t)) {
+            return true;
+          }
+        }
+      }
+      return false;
+    }
+
+    private LiquidNode parseIf(String cnt, boolean inLoop) throws FHIRException {
       LiquidIf res = new LiquidIf();
       res.condition = cnt.substring(3).trim();
-      String term = parseList(res.thenBody, new String[] { "else", "endif"} );
+      String term = parseList(res.thenBody, inLoop, new String[] { "else", "elsif ", "endif" });
-      if ("else".equals(term))
+      while (term.startsWith("elsif ")) {
-        term = parseList(res.elseBody, new String[] { "endif"} );
+        LiquidElsIf elsIf = new LiquidElsIf();
+        res.elseIf.add(elsIf);
+        elsIf.condition = term.substring(5).trim();
+        term = parseList(elsIf.body, inLoop, new String[] { "elsif ", "else", "endif" });
+      }
+      if ("else".equals(term)) {
+        term = parseList(res.elseBody, inLoop, new String[] { "endif" });
+      }
+
       return res;
     }
 
@@ -291,7 +495,7 @@ public class LiquidEngine implements IEvaluationContext {
       while (i < cnt.length() && !Character.isWhitespace(cnt.charAt(i)))
         i++;
       if (i == cnt.length() || i == 0)
-        throw new FHIRException("Script "+name+": Error reading include: "+cnt);
+        throw new FHIRException("Script " + name + ": Error reading include: " + cnt);
       LiquidInclude res = new LiquidInclude();
       res.page = cnt.substring(0, i);
       while (i < cnt.length() && Character.isWhitespace(cnt.charAt(i)))
@@ -300,27 +504,26 @@ public class LiquidEngine implements IEvaluationContext {
         int j = i;
         while (i < cnt.length() && cnt.charAt(i) != '=')
           i++;
-        if (i >= cnt.length() || j == i) 
+        if (i >= cnt.length() || j == i)
-          throw new FHIRException("Script "+name+": Error reading include: "+cnt);
+          throw new FHIRException("Script " + name + ": Error reading include: " + cnt);
         String n = cnt.substring(j, i);
-          if (res.params.containsKey(n)) 
+        if (res.params.containsKey(n))
-            throw new FHIRException("Script "+name+": Error reading include: "+cnt);
+          throw new FHIRException("Script " + name + ": Error reading include: " + cnt);
+        i++;
+        ExpressionNodeWithOffset t = engine.parsePartial(cnt, i);
+        i = t.getOffset();
+        res.params.put(n, t.getNode());
+        while (i < cnt.length() && Character.isWhitespace(cnt.charAt(i)))
           i++;
-          ExpressionNodeWithOffset t = engine.parsePartial(cnt, i);
-          i = t.getOffset();
-          res.params.put(n, t.getNode());
-          while (i < cnt.length() && Character.isWhitespace(cnt.charAt(i)))
-            i++;
       }
       return res;
     }
-  
 
     private LiquidNode parseLoop(String cnt) throws FHIRException {
       int i = 0;
       while (!Character.isWhitespace(cnt.charAt(i)))
         i++;
-      LiquidLoop res = new LiquidLoop();
+      LiquidFor res = new LiquidFor();
       res.varName = cnt.substring(0, i);
       while (Character.isWhitespace(cnt.charAt(i)))
         i++;
@@ -328,36 +531,58 @@ public class LiquidEngine implements IEvaluationContext {
       while (!Character.isWhitespace(cnt.charAt(i)))
         i++;
       if (!"in".equals(cnt.substring(j, i)))
-        throw new FHIRException("Script "+name+": Script "+name+": Error reading loop: "+cnt);
+        throw new FHIRException("Script " + name + ": Script " + name + ": Error reading loop: " + cnt);
       res.condition = cnt.substring(i).trim();
-      parseList(res.body, new String[] { "endloop"} );
+      parseList(res.body, false, new String[] { "endloop" });
       return res;
     }
 
+    private LiquidNode parseFor(String cnt) throws FHIRException {
+      int i = 0;
+      while (!Character.isWhitespace(cnt.charAt(i)))
+        i++;
+      LiquidFor res = new LiquidFor();
+      res.varName = cnt.substring(0, i);
+      while (Character.isWhitespace(cnt.charAt(i)))
+        i++;
+      int j = i;
+      while (!Character.isWhitespace(cnt.charAt(i)))
+        i++;
+      if (!"in".equals(cnt.substring(j, i)))
+        throw new FHIRException("Script " + name + ": Script " + name + ": Error reading loop: " + cnt);
+      res.condition = cnt.substring(i).trim();
+      String term = parseList(res.body, true, new String[] { "endfor", "else" });
+      if ("else".equals(term)) {
+        parseList(res.elseBody, false, new String[] { "endfor" });
+      }
+      return res;
+    }
+
+
     private String parseTag(char ch) throws FHIRException {
-      grab(); 
+      grab();
       grab();
       StringBuilder b = new StringBuilder();
       while (cursor < source.length() && !(next1() == '%' && next2() == '}')) {
         b.append(grab());
       }
-      if (!(next1() == '%' && next2() == '}')) 
+      if (!(next1() == '%' && next2() == '}'))
-        throw new FHIRException("Script "+name+": Unterminated Liquid statement {% "+b.toString());
+        throw new FHIRException("Script " + name + ": Unterminated Liquid statement {% " + b.toString());
-      grab(); 
+      grab();
       grab();
       return b.toString().trim();
     }
 
     private LiquidStatement parseStatement() throws FHIRException {
-      grab(); 
+      grab();
       grab();
       StringBuilder b = new StringBuilder();
       while (cursor < source.length() && !(next1() == '}' && next2() == '}')) {
         b.append(grab());
       }
-      if (!(next1() == '}' && next2() == '}')) 
+      if (!(next1() == '}' && next2() == '}'))
-        throw new FHIRException("Script "+name+": Unterminated Liquid statement {{ "+b.toString());
+        throw new FHIRException("Script " + name + ": Unterminated Liquid statement {{ " + b.toString());
-      grab(); 
+      grab();
       grab();
       LiquidStatement res = new LiquidStatement();
       res.statement = b.toString().trim();
@@ -471,7 +696,7 @@ public class LiquidEngine implements IEvaluationContext {
         if (!cnt.equals(node.getAttributes().get(an))) {
           node.getAttributes().put(an, cnt);
           replaced = true;
-        }        
+        }
       }
     }
     return replaced;

org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/test/LiquidEngineTests.java

@@ -57,7 +57,7 @@ public class LiquidEngineTests implements ILiquidEngineIcludeResolver {
     this.test = test;
     LiquidDocument doc = engine.parse(test.get("template").getAsString(), "test-script");
     String output = engine.evaluate(doc, loadResource(), null);
-    Assertions.assertTrue(test.get("output").getAsString().equals(output));
+    Assertions.assertEquals(test.get("output").getAsString(), output);
   }
 
   @Override