Merge pull request #20 from carocad/symbols

Symbols and macro keyword patterns

project.clj

@@ -1,4 +1,4 @@
-(defproject carocad/parcera "0.3.0"
+(defproject carocad/parcera "0.3.1"
   :description "Grammar-based Clojure(script) parser"
   :url "https://github.com/carocad/parcera"
   :license {:name "LGPLv3"

src/parcera/terminals.cljc

@@ -1,15 +1,28 @@
-(ns parcera.terminals)
+(ns parcera.terminals
+  "Clojure symbols, keywords, numbers and string/regex share quite a lot
+  of matching logic. This namespace is aimed towards clearly identifying
+  those pieces and share them among the different definitions to
+  avoid recurring issues")
 
-; todo: anchor ALL to the beginning of string
-; todo: try to avoid lookahead
+;; Clojure's reader is quite permissive so we follow the motto
+;; "if it is not forbidden, it is allowed"
+(def not-allowed "\\s\\(\\)\\[\\]{}\"@~\\^;`\\\\\\/,")
+(def allowed-characters (str "[^" not-allowed "]*"))
+(def not-number "(?![+-]?\\d+)")
+(def symbol-end "(?=[\\s\"()\\[\\]{},]|$)")
+
+(defn- name-pattern
+  [restriction]
+  (let [first-character (str "[^" restriction not-allowed "]")]
+    (str "(" first-character allowed-characters "\\/)?"
+         "(\\/|(" first-character allowed-characters "))"
+         symbol-end)))
+
+
+(def symbol-pattern (str not-number (name-pattern ":#\\'")))
+(def simple-keyword (str ":" (name-pattern ":")))
+(def macro-keyword (str "::" (name-pattern ":")))
 
-;; Clojure's reader is quite permissive so we follow the motto "if it is not forbidden, it is allowed"
-; todo: dont allow /
-(def NAME "[^\\s\\(\\)\\[\\]{}\"@~\\^;`\\\\]+")
-; todo: (?!\/) do i need that ?
-;; symbols cannot start with a number, :, # nor '
-; todo: no need for negative lookahead of chars
-(def symbol-pattern (str "(?![:#\\',]|[+-]?\\d+)(" NAME "\\/)?(\\/|(" NAME "))"))
 
 (def double-suffix "(((\\.\\d*)?([eE][-+]?\\d+)?)M?)")
 (def long-suffix "((0[xX]([\\dA-Fa-f]+)|0([0-7]+)|([1-9]\\d?)[rR]([\\d\\w]+)|0\\d+)?N?)")
@@ -21,19 +34,11 @@
 ; mentioned here: https://www.regular-expressions.info/unicode.html
 ; It's cooked by this generator: http://kourge.net/projects/regexp-unicode-block
 ; ticking all 'Combining Diacritical Marks' boxes *))
-; todo: repeated pattern could be simplified
-(def unicode-char "([^\\u0300-\\u036F\\u1DC0-\\u1DFF\\u20D0-\\u20FF][\\u0300-\\u036F\\u1DC0-\\u1DFF\\u20D0-\\u20FF]*)")
+(def unicode-char "([^\\u0300-\\u036F\\u1DC0-\\u1DFF\\u20D0-\\u20FF])")
 (def named-char "(newline|return|space|tab|formfeed|backspace)")
 (def unicode "(u[\\dD-Fd-f]{4})")
-; todo: use word boundary to avoid lookahead
 (def character-pattern (str "\\\\(" unicode-char "|" named-char "|" unicode ")(?!\\w+)"))
 
 
-; : is not allowed as first keyword character
-; todo: no need for negative lookahead of symbol
-(def simple-keyword (str ":(?!:)" symbol-pattern))
-(def macro-keyword (str "::(?!:)" NAME))
-
-
 (def string-pattern "\"[^\"\\\\]*(?:\\\\.[^\"\\\\]*)*\"")
 (def regex-pattern (str "#" string-pattern))

test/parcera/test/core.cljc

@@ -132,7 +132,11 @@
     (as-> "{:hello ;2}
            2}" input (and (is (valid? input))
                           (is (roundtrip input))
-                          (is (clear input))))))
+                          (is (clear input)))))
+  (testing "symbols"
+    (as-> "hello/world/" input (is (not (valid? input))))
+    (as-> ":hello/world/" input (is (not (valid? input))))
+    (as-> "::hello/world/" input (is (not (valid? input))))))
 
 
 (deftest macros