From b2618adaea72021c69603a4a1dd1a1d0a75ae439 Mon Sep 17 00:00:00 2001
From: Jorge Izquierdo <jorge@izqui.me>
Date: Tue, 13 Nov 2018 11:21:49 +0100
Subject: [PATCH] Fix empty strings

---
 package-lock.json         | 74 +++++++++++++++++++--------------------
 src/evaluator/index.js    |  2 +-
 test/examples/examples.js |  4 +++
 3 files changed, 42 insertions(+), 38 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index dcc8f34..f7a39a1 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1662,7 +1662,7 @@
         },
         "chalk": {
           "version": "1.1.3",
-          "resolved": "http://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
+          "resolved": "https://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
           "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
           "dev": true,
           "requires": {
@@ -1681,7 +1681,7 @@
         },
         "strip-ansi": {
           "version": "3.0.1",
-          "resolved": "http://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
+          "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
           "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
           "dev": true,
           "requires": {
@@ -2191,7 +2191,7 @@
     },
     "browserify-aes": {
       "version": "1.2.0",
-      "resolved": "http://registry.npmjs.org/browserify-aes/-/browserify-aes-1.2.0.tgz",
+      "resolved": "https://registry.npmjs.org/browserify-aes/-/browserify-aes-1.2.0.tgz",
       "integrity": "sha512-+7CHXqGuspUn/Sl5aO7Ea0xWGAtETPXNSAjHo48JfLdPWcMng33Xe4znFvQweqc/uzk5zSOI3H52CYnjCfb5hA==",
       "requires": {
         "buffer-xor": "^1.0.3",
@@ -2225,7 +2225,7 @@
     },
     "browserify-rsa": {
       "version": "4.0.1",
-      "resolved": "http://registry.npmjs.org/browserify-rsa/-/browserify-rsa-4.0.1.tgz",
+      "resolved": "https://registry.npmjs.org/browserify-rsa/-/browserify-rsa-4.0.1.tgz",
       "integrity": "sha1-IeCr+vbyApzy+vsTNWenAdQTVSQ=",
       "requires": {
         "bn.js": "^4.1.0",
@@ -2606,7 +2606,7 @@
         },
         "strip-ansi": {
           "version": "3.0.1",
-          "resolved": "http://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
+          "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
           "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
           "dev": true,
           "requires": {
@@ -2876,7 +2876,7 @@
       "dependencies": {
         "minimist": {
           "version": "1.2.0",
-          "resolved": "http://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
           "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
           "dev": true
         }
@@ -2902,7 +2902,7 @@
     },
     "create-hash": {
       "version": "1.2.0",
-      "resolved": "http://registry.npmjs.org/create-hash/-/create-hash-1.2.0.tgz",
+      "resolved": "https://registry.npmjs.org/create-hash/-/create-hash-1.2.0.tgz",
       "integrity": "sha512-z00bCGNHDG8mHAkP7CtT1qVu+bFQUPjYq/4Iv3C3kWjTFV10zIjfSoeqXo9Asws8gwSHDGj/hl2u4OGIjapeCg==",
       "requires": {
         "cipher-base": "^1.0.1",
@@ -2914,7 +2914,7 @@
     },
     "create-hmac": {
       "version": "1.1.7",
-      "resolved": "http://registry.npmjs.org/create-hmac/-/create-hmac-1.1.7.tgz",
+      "resolved": "https://registry.npmjs.org/create-hmac/-/create-hmac-1.1.7.tgz",
       "integrity": "sha512-MJG9liiZ+ogc4TzUwuvbER1JRdgvUFSB5+VR/g5h82fGaIRWMWddtKBHi7/sVhfjQZ6SehlyhvQYrcYkaUIpLg==",
       "requires": {
         "cipher-base": "^1.0.3",
@@ -3174,7 +3174,7 @@
           "dependencies": {
             "pify": {
               "version": "2.3.0",
-              "resolved": "http://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
+              "resolved": "https://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
               "integrity": "sha1-7RQaasBDqEnqWISY59yosVMw6Qw=",
               "dev": true
             }
@@ -3233,7 +3233,7 @@
     },
     "diffie-hellman": {
       "version": "5.0.3",
-      "resolved": "http://registry.npmjs.org/diffie-hellman/-/diffie-hellman-5.0.3.tgz",
+      "resolved": "https://registry.npmjs.org/diffie-hellman/-/diffie-hellman-5.0.3.tgz",
       "integrity": "sha512-kqag/Nl+f3GwyK25fhUMYj81BUOrZ9IuJsjIcDE5icNM9FJHAVm3VcUDxdLPoQtTuUylWm6ZIknYJwwaPxsUzg==",
       "requires": {
         "bn.js": "^4.1.0",
@@ -3861,7 +3861,7 @@
         },
         "pify": {
           "version": "2.3.0",
-          "resolved": "http://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
+          "resolved": "https://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
           "integrity": "sha1-7RQaasBDqEnqWISY59yosVMw6Qw=",
           "dev": true
         },
@@ -4357,7 +4357,7 @@
     },
     "finalhandler": {
       "version": "1.1.1",
-      "resolved": "http://registry.npmjs.org/finalhandler/-/finalhandler-1.1.1.tgz",
+      "resolved": "https://registry.npmjs.org/finalhandler/-/finalhandler-1.1.1.tgz",
       "integrity": "sha512-Y1GUDo39ez4aHAw7MysnUD5JzYX+WaIj8I57kO3aEPT1fFRL4sr7mjei97FgnwhAyyzRYmQZaTHb2+9uZ1dPtg==",
       "requires": {
         "debug": "2.6.9",
@@ -4445,7 +4445,7 @@
         },
         "pify": {
           "version": "2.3.0",
-          "resolved": "http://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
+          "resolved": "https://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
           "integrity": "sha1-7RQaasBDqEnqWISY59yosVMw6Qw=",
           "dev": true
         }
@@ -5092,7 +5092,7 @@
     },
     "get-stream": {
       "version": "3.0.0",
-      "resolved": "http://registry.npmjs.org/get-stream/-/get-stream-3.0.0.tgz",
+      "resolved": "https://registry.npmjs.org/get-stream/-/get-stream-3.0.0.tgz",
       "integrity": "sha1-jpQ9E1jcN1VQVOy+LtsFqhdO3hQ=",
       "dev": true
     },
@@ -5245,7 +5245,7 @@
     },
     "got": {
       "version": "6.7.1",
-      "resolved": "http://registry.npmjs.org/got/-/got-6.7.1.tgz",
+      "resolved": "https://registry.npmjs.org/got/-/got-6.7.1.tgz",
       "integrity": "sha1-JAzQV4WpoY5WHcG0S0HHY+8ejbA=",
       "dev": true,
       "requires": {
@@ -5457,7 +5457,7 @@
     },
     "http-errors": {
       "version": "1.6.3",
-      "resolved": "http://registry.npmjs.org/http-errors/-/http-errors-1.6.3.tgz",
+      "resolved": "https://registry.npmjs.org/http-errors/-/http-errors-1.6.3.tgz",
       "integrity": "sha1-i1VoC7S+KDoLW/TqLjhYC+HZMg0=",
       "requires": {
         "depd": "~1.1.2",
@@ -5743,7 +5743,7 @@
     },
     "is-builtin-module": {
       "version": "1.0.0",
-      "resolved": "http://registry.npmjs.org/is-builtin-module/-/is-builtin-module-1.0.0.tgz",
+      "resolved": "https://registry.npmjs.org/is-builtin-module/-/is-builtin-module-1.0.0.tgz",
       "integrity": "sha1-VAVy0096wxGfj3bDDLwbHgN6/74=",
       "dev": true,
       "requires": {
@@ -5908,7 +5908,7 @@
     },
     "is-obj": {
       "version": "1.0.1",
-      "resolved": "http://registry.npmjs.org/is-obj/-/is-obj-1.0.1.tgz",
+      "resolved": "https://registry.npmjs.org/is-obj/-/is-obj-1.0.1.tgz",
       "integrity": "sha1-PkcprB9f3gJc19g6iW2rn09n2w8=",
       "dev": true
     },
@@ -6181,7 +6181,7 @@
     },
     "json5": {
       "version": "0.5.1",
-      "resolved": "http://registry.npmjs.org/json5/-/json5-0.5.1.tgz",
+      "resolved": "https://registry.npmjs.org/json5/-/json5-0.5.1.tgz",
       "integrity": "sha1-Hq3nrMASA0rYTiOWdn6tn6VJWCE=",
       "dev": true
     },
@@ -6587,7 +6587,7 @@
     },
     "media-typer": {
       "version": "0.3.0",
-      "resolved": "http://registry.npmjs.org/media-typer/-/media-typer-0.3.0.tgz",
+      "resolved": "https://registry.npmjs.org/media-typer/-/media-typer-0.3.0.tgz",
       "integrity": "sha1-hxDXrwqmJvj/+hzgAWhUUmMlV0g="
     },
     "mem": {
@@ -6714,7 +6714,7 @@
     },
     "minimist": {
       "version": "0.0.8",
-      "resolved": "http://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz",
+      "resolved": "https://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz",
       "integrity": "sha1-hX/Kv8M5fSYluCKCYuhqp6ARsF0=",
       "dev": true
     },
@@ -6751,7 +6751,7 @@
     },
     "mkdirp": {
       "version": "0.5.1",
-      "resolved": "http://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz",
+      "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz",
       "integrity": "sha1-MAV0OOrGz3+MR2fzhkjWaX11yQM=",
       "dev": true,
       "requires": {
@@ -6793,7 +6793,7 @@
           "dependencies": {
             "readable-stream": {
               "version": "2.0.6",
-              "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-2.0.6.tgz",
+              "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.0.6.tgz",
               "integrity": "sha1-j5A0HmilPMySh4jaz80Rs265t44=",
               "dev": true,
               "requires": {
@@ -6846,7 +6846,7 @@
     },
     "nan": {
       "version": "2.10.0",
-      "resolved": "http://registry.npmjs.org/nan/-/nan-2.10.0.tgz",
+      "resolved": "https://registry.npmjs.org/nan/-/nan-2.10.0.tgz",
       "integrity": "sha512-bAdJv7fBLhWC+/Bls0Oza+mvTaNQtP+1RyhhhvD95pgUJz6XM5IzgmxOkItJ9tkoCiplvAnXI1tNmmUD/eScyA=="
     },
     "nano-json-stream-parser": {
@@ -9890,7 +9890,7 @@
     },
     "parse-asn1": {
       "version": "5.1.1",
-      "resolved": "http://registry.npmjs.org/parse-asn1/-/parse-asn1-5.1.1.tgz",
+      "resolved": "https://registry.npmjs.org/parse-asn1/-/parse-asn1-5.1.1.tgz",
       "integrity": "sha512-KPx7flKXg775zZpnp9SxJlz00gTd4BmJ2yJufSc44gMCRrRQ7NSzAcSJQfifuOLgW6bEi+ftrALtsgALeB2Adw==",
       "requires": {
         "asn1.js": "^4.0.0",
@@ -10290,7 +10290,7 @@
     },
     "query-string": {
       "version": "5.1.1",
-      "resolved": "http://registry.npmjs.org/query-string/-/query-string-5.1.1.tgz",
+      "resolved": "https://registry.npmjs.org/query-string/-/query-string-5.1.1.tgz",
       "integrity": "sha512-gjWOsm2SoGlgLEdAGt7a6slVOk9mGiXmPFMqrEhLQ68rhQuBnpfs3+EmlvqKyxnCo9/PPlF+9MtY02S1aFg+Jw==",
       "requires": {
         "decode-uri-component": "^0.2.0",
@@ -10356,7 +10356,7 @@
       "dependencies": {
         "minimist": {
           "version": "1.2.0",
-          "resolved": "http://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
           "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
           "dev": true
         }
@@ -10385,7 +10385,7 @@
     },
     "readable-stream": {
       "version": "2.3.6",
-      "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-2.3.6.tgz",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.6.tgz",
       "integrity": "sha512-tQtKA9WIAhBF3+VLAseyMqZeBjW0AHJoxOtYqSUZNJxauErmLbVm2FW1y+J/YA9dUrAC39ITejlZWhVIwawkKw==",
       "dev": true,
       "requires": {
@@ -11006,7 +11006,7 @@
     },
     "sha.js": {
       "version": "2.4.11",
-      "resolved": "http://registry.npmjs.org/sha.js/-/sha.js-2.4.11.tgz",
+      "resolved": "https://registry.npmjs.org/sha.js/-/sha.js-2.4.11.tgz",
       "integrity": "sha512-QMEp5B7cftE7APOjk5Y6xgrbWu+WkLVQwk8JNjZ8nKRciZaByEW6MubieAiToS7+dwvrjGhH8jRXz3MVd0AYqQ==",
       "requires": {
         "inherits": "^2.0.1",
@@ -11346,7 +11346,7 @@
       "dependencies": {
         "minimist": {
           "version": "1.2.0",
-          "resolved": "http://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
           "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
           "dev": true
         }
@@ -11401,7 +11401,7 @@
         },
         "readable-stream": {
           "version": "2.1.5",
-          "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-2.1.5.tgz",
+          "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.1.5.tgz",
           "integrity": "sha1-ZvqLcg4UOLNkaB8q0aY8YYRIydA=",
           "dev": true,
           "requires": {
@@ -11560,7 +11560,7 @@
       "dependencies": {
         "minimist": {
           "version": "1.2.0",
-          "resolved": "http://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
           "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
           "dev": true
         }
@@ -11662,7 +11662,7 @@
     },
     "through": {
       "version": "2.3.8",
-      "resolved": "http://registry.npmjs.org/through/-/through-2.3.8.tgz",
+      "resolved": "https://registry.npmjs.org/through/-/through-2.3.8.tgz",
       "integrity": "sha1-DdTJ/6q8NXlgsbckEV1+Doai4fU=",
       "dev": true
     },
@@ -12552,7 +12552,7 @@
         },
         "uuid": {
           "version": "2.0.1",
-          "resolved": "http://registry.npmjs.org/uuid/-/uuid-2.0.1.tgz",
+          "resolved": "https://registry.npmjs.org/uuid/-/uuid-2.0.1.tgz",
           "integrity": "sha1-wqMN7bPlNdcsz4LjQ5QaULqFM6w="
         }
       }
@@ -12710,7 +12710,7 @@
     },
     "wrap-ansi": {
       "version": "2.1.0",
-      "resolved": "http://registry.npmjs.org/wrap-ansi/-/wrap-ansi-2.1.0.tgz",
+      "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-2.1.0.tgz",
       "integrity": "sha1-2Pw9KE3QV5T+hJc8rs3Rz4JP3YU=",
       "dev": true,
       "requires": {
@@ -12746,7 +12746,7 @@
         },
         "strip-ansi": {
           "version": "3.0.1",
-          "resolved": "http://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
+          "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
           "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
           "dev": true,
           "requires": {
@@ -12915,7 +12915,7 @@
         },
         "pify": {
           "version": "2.3.0",
-          "resolved": "http://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
+          "resolved": "https://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
           "integrity": "sha1-7RQaasBDqEnqWISY59yosVMw6Qw=",
           "dev": true
         },
diff --git a/src/evaluator/index.js b/src/evaluator/index.js
index 3fba5fb..fb8b905 100644
--- a/src/evaluator/index.js
+++ b/src/evaluator/index.js
@@ -98,7 +98,7 @@ class Evaluator {
     }
 
     if (node.type === 'StringLiteral') {
-      return new TypedValue('string', node.value)
+      return new TypedValue('string', node.value || '')
     }
 
     if (node.type === 'NumberLiteral') {
diff --git a/test/examples/examples.js b/test/examples/examples.js
index c873b8a..a342ae7 100644
--- a/test/examples/examples.js
+++ b/test/examples/examples.js
@@ -166,6 +166,10 @@ const cases = [
     source: 'a is `a`, b is `b` and "c d" is `c d`',
     bindings: { a: int(1), b: int(2), c: int(3), d: int(4) }
   }, 'a is 1, b is 2 and "c d" is 3 4'],
+  [{
+    source: 'An empty string`\'\'`',
+    bindings: { }
+  }, 'An empty string'],
 
   // Maths
   [{