diff --git a/lib/compiler/passes/generate-javascript.js b/lib/compiler/passes/generate-javascript.js
index fb159e7..10b0f77 100644
--- a/lib/compiler/passes/generate-javascript.js
+++ b/lib/compiler/passes/generate-javascript.js
@@ -887,8 +887,7 @@ function generateJavascript(ast, options) {
     '',
     '        peg$currPos          = 0,',
     '        peg$savedPos         = 0,',
-    '        peg$cachedPos        = 0,',
-    '        peg$cachedPosDetails = { line: 1, column: 1, seenCR: false },',
+    '        peg$posDetailsCache  = [{ line: 1, column: 1, seenCR: false }],',
     '        peg$maxFailPos       = 0,',
     '        peg$maxFailExpected  = [],',
     '        peg$silentFails      = 0,',   // 0 = report failures, > 0 = silence failures
@@ -979,10 +978,25 @@ function generateJavascript(ast, options) {
     '    }',
     '',
     '    function peg$computePosDetails(pos) {',
-    '      function advance(details, startPos, endPos) {',
-    '        var p, ch;',
+    '      var details = peg$posDetailsCache[pos],',
+    '          p, ch;',
     '',
-    '        for (p = startPos; p < endPos; p++) {',
+    '      if (details) {',
+    '        return details;',
+    '      } else {',
+    '        p = pos - 1;',
+    '        while (!peg$posDetailsCache[p]) {',
+    '          p--;',
+    '        }',
+    '',
+    '        details = peg$posDetailsCache[p];',
+    '        details = {',
+    '          line:   details.line,',
+    '          column: details.column,',
+    '          seenCR: details.seenCR',
+    '        };',
+    '',
+    '        while (p < pos) {',
     '          ch = input.charAt(p);',
     '          if (ch === "\\n") {',
     '            if (!details.seenCR) { details.line++; }',
@@ -996,23 +1010,13 @@ function generateJavascript(ast, options) {
     '            details.column++;',
     '            details.seenCR = false;',
     '          }',
-    '        }',
-    '      }',
     '',
-    '      if (peg$cachedPos !== pos) {',
-    '        if (peg$cachedPos > pos) {',
-    '          peg$cachedPos = 0;',
-    '          peg$cachedPosDetails = { line: 1, column: 1, seenCR: false };',
+    '          p++',
     '        }',
-    '        advance(peg$cachedPosDetails, peg$cachedPos, pos);',
-    '        peg$cachedPos = pos;',
-    '      }',
     '',
-    '      return {',
-    '        line:   peg$cachedPosDetails.line,',
-    '        column: peg$cachedPosDetails.column,',
-    '        seenCR: peg$cachedPosDetails.seenCR',
-    '      };',
+    '        peg$posDetailsCache[pos] = details;',
+    '        return details',
+    '      }',
     '    }',
     '',
     '    function peg$computeLocation(startPos, endPos) {',
diff --git a/lib/parser.js b/lib/parser.js
index 290c013..22cf052 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -375,8 +375,7 @@ module.exports = (function() {
 
         peg$currPos          = 0,
         peg$savedPos         = 0,
-        peg$cachedPos        = 0,
-        peg$cachedPosDetails = { line: 1, column: 1, seenCR: false },
+        peg$posDetailsCache  = [{ line: 1, column: 1, seenCR: false }],
         peg$maxFailPos       = 0,
         peg$maxFailExpected  = [],
         peg$silentFails      = 0,
@@ -418,10 +417,25 @@ module.exports = (function() {
     }
 
     function peg$computePosDetails(pos) {
-      function advance(details, startPos, endPos) {
-        var p, ch;
+      var details = peg$posDetailsCache[pos],
+          p, ch;
 
-        for (p = startPos; p < endPos; p++) {
+      if (details) {
+        return details;
+      } else {
+        p = pos - 1;
+        while (!peg$posDetailsCache[p]) {
+          p--;
+        }
+
+        details = peg$posDetailsCache[p];
+        details = {
+          line:   details.line,
+          column: details.column,
+          seenCR: details.seenCR
+        };
+
+        while (p < pos) {
           ch = input.charAt(p);
           if (ch === "\n") {
             if (!details.seenCR) { details.line++; }
@@ -435,23 +449,13 @@ module.exports = (function() {
             details.column++;
             details.seenCR = false;
           }
-        }
-      }
 
-      if (peg$cachedPos !== pos) {
-        if (peg$cachedPos > pos) {
-          peg$cachedPos = 0;
-          peg$cachedPosDetails = { line: 1, column: 1, seenCR: false };
+          p++
         }
-        advance(peg$cachedPosDetails, peg$cachedPos, pos);
-        peg$cachedPos = pos;
-      }
 
-      return {
-        line:   peg$cachedPosDetails.line,
-        column: peg$cachedPosDetails.column,
-        seenCR: peg$cachedPosDetails.seenCR
-      };
+        peg$posDetailsCache[pos] = details;
+        return details
+      }
     }
 
     function peg$computeLocation(startPos, endPos) {