Fix parsing of theme() inside calc() when there are no spaces around operators (#11157)

* Refactor

* Don’t resolve functions for anything not using theme or screen

* Normalize math operators inside calc when handling functions

* Inline postcss-value-parser

* Treat all functions the same as calc

* Remove workaround for calc + operators without spaces

* Remove `postcss-value-parser` dependency

* Update lockfile

* Update sourcemaps

* Update changelog

* Update `value-parser` formatting

* Stop prettier from complaining

src/value-parser/stringify.js

@@ -0,0 +1,41 @@
+function stringifyNode(node, custom) {
+  var type = node.type
+  var value = node.value
+  var buf
+  var customResult
+
+  if (custom && (customResult = custom(node)) !== undefined) {
+    return customResult
+  } else if (type === 'word' || type === 'space') {
+    return value
+  } else if (type === 'string') {
+    buf = node.quote || ''
+    return buf + value + (node.unclosed ? '' : buf)
+  } else if (type === 'comment') {
+    return '/*' + value + (node.unclosed ? '' : '*/')
+  } else if (type === 'div') {
+    return (node.before || '') + value + (node.after || '')
+  } else if (Array.isArray(node.nodes)) {
+    buf = stringify(node.nodes, custom)
+    if (type !== 'function') {
+      return buf
+    }
+    return value + '(' + (node.before || '') + buf + (node.after || '') + (node.unclosed ? '' : ')')
+  }
+  return value
+}
+
+function stringify(nodes, custom) {
+  var result, i
+
+  if (Array.isArray(nodes)) {
+    result = ''
+    for (i = nodes.length - 1; ~i; i -= 1) {
+      result = stringifyNode(nodes[i], custom) + result
+    }
+    return result
+  }
+  return stringifyNode(nodes, custom)
+}
+
+module.exports = stringify