switch to vuepress

1 files changed, 138 insertions, 0 deletions

diff --git a/node_modules/spdx-expression-parse/parse.js b/node_modules/spdx-expression-parse/parse.js
new file mode 100644
index 00000000..a4a52ce9
--- /dev/null
+++ b/node_modules/spdx-expression-parse/parse.js
@@ -0,0 +1,138 @@
+'use strict'
+
+// The ABNF grammar in the spec is totally ambiguous.
+//
+// This parser follows the operator precedence defined in the
+// `Order of Precedence and Parentheses` section.
+
+module.exports = function (tokens) {
+  var index = 0
+
+  function hasMore () {
+    return index < tokens.length
+  }
+
+  function token () {
+    return hasMore() ? tokens[index] : null
+  }
+
+  function next () {
+    if (!hasMore()) {
+      throw new Error()
+    }
+    index++
+  }
+
+  function parseOperator (operator) {
+    var t = token()
+    if (t && t.type === 'OPERATOR' && operator === t.string) {
+      next()
+      return t.string
+    }
+  }
+
+  function parseWith () {
+    if (parseOperator('WITH')) {
+      var t = token()
+      if (t && t.type === 'EXCEPTION') {
+        next()
+        return t.string
+      }
+      throw new Error('Expected exception after `WITH`')
+    }
+  }
+
+  function parseLicenseRef () {
+    // TODO: Actually, everything is concatenated into one string
+    // for backward-compatibility but it could be better to return
+    // a nice structure.
+    var begin = index
+    var string = ''
+    var t = token()
+    if (t.type === 'DOCUMENTREF') {
+      next()
+      string += 'DocumentRef-' + t.string + ':'
+      if (!parseOperator(':')) {
+        throw new Error('Expected `:` after `DocumentRef-...`')
+      }
+    }
+    t = token()
+    if (t.type === 'LICENSEREF') {
+      next()
+      string += 'LicenseRef-' + t.string
+      return {license: string}
+    }
+    index = begin
+  }
+
+  function parseLicense () {
+    var t = token()
+    if (t && t.type === 'LICENSE') {
+      next()
+      var node = {license: t.string}
+      if (parseOperator('+')) {
+        node.plus = true
+      }
+      var exception = parseWith()
+      if (exception) {
+        node.exception = exception
+      }
+      return node
+    }
+  }
+
+  function parseParenthesizedExpression () {
+    var left = parseOperator('(')
+    if (!left) {
+      return
+    }
+
+    var expr = parseExpression()
+
+    if (!parseOperator(')')) {
+      throw new Error('Expected `)`')
+    }
+
+    return expr
+  }
+
+  function parseAtom () {
+    return (
+      parseParenthesizedExpression() ||
+      parseLicenseRef() ||
+      parseLicense()
+    )
+  }
+
+  function makeBinaryOpParser (operator, nextParser) {
+    return function parseBinaryOp () {
+      var left = nextParser()
+      if (!left) {
+        return
+      }
+
+      if (!parseOperator(operator)) {
+        return left
+      }
+
+      var right = parseBinaryOp()
+      if (!right) {
+        throw new Error('Expected expression')
+      }
+      return {
+        left: left,
+        conjunction: operator.toLowerCase(),
+        right: right
+      }
+    }
+  }
+
+  var parseAnd = makeBinaryOpParser('AND', parseAtom)
+  var parseExpression = makeBinaryOpParser('OR', parseAnd)
+
+  var node = parseExpression()
+  if (!node || hasMore()) {
+    throw new Error('Syntax error')
+  }
+  return node
+}