[elpa] externals/parser-generator c0310bf 169/434: Added error-handling to lexical analyser

[ELPA Syncer]

branch: externals/parser-generator
commit c0310bf426180199844413b67ec9c6624b59b1f1
Author: Christian Johansson <christian@cvj.se>
Commit: Christian Johansson <christian@cvj.se>

    Added error-handling to lexical analyser
---
 parser-generator-lex-analyzer.el           | 89 +++++++++++++++++++-----------
 test/parser-generator-lex-analyzer-test.el | 27 ++++++++-
 2 files changed, 82 insertions(+), 34 deletions(-)

diff --git a/parser-generator-lex-analyzer.el b/parser-generator-lex-analyzer.el
index b9f30c3..6f0609f 100644
--- a/parser-generator-lex-analyzer.el
+++ b/parser-generator-lex-analyzer.el
@@ -15,11 +15,11 @@
 
 (defvar parser-generator-lex-analyzer--get-function
   nil
-  "Get token information function.")
+  "Get token information function.  This function will be called when building 
token meta-information before calling optional syntax-directed translation / 
semantic-actions.  Anything other than nil is expected.")
 
 (defvar parser-generator-lex-analyzer--function
   nil
-  "Function used as lex-analyzer.")
+  "Function used as lex-analyzer.  This function will be called and as result 
a list with structure '(a b . c) is expected where a is a string or symbol, if 
no more tokens can be found nil is expected, if it's not possible to proceed 
lex analysis an error-signal is expected.")
 
 (defvar parser-generator-lex-analyzer--index
   nil
@@ -33,14 +33,24 @@
 ;; Functions
 
 
-;; TODO Catch errors
 (defun parser-generator-lex-analyzer--get-function (token)
   "Get information about TOKEN."
   (unless parser-generator-lex-analyzer--get-function
     (error "Missing lex-analyzer get function!"))
-  (funcall parser-generator-lex-analyzer--get-function token))
+  (let ((meta-information))
+    (condition-case error
+        (progn
+          (setq meta-information (funcall
+                                  parser-generator-lex-analyzer--get-function
+                                  token)))
+      (error (error
+              "Lex-analyze failed to get token meta-data of %s, error: %s"
+              token
+              (car (cdr error)))))
+    (unless meta-information
+      (error "Could not find any token meta-information for: %s" token))
+    meta-information))
 
-;; TODO Catch errors
 (defun parser-generator-lex-analyzer--peek-next-look-ahead ()
   "Peek next look-ahead number of tokens via lex-analyzer."
   (unless parser-generator-lex-analyzer--index
@@ -52,41 +62,56 @@
   (let ((look-ahead)
         (look-ahead-length 0)
         (index parser-generator-lex-analyzer--index))
-    (while (< look-ahead-length parser-generator--look-ahead-number)
-      (let ((next-look-ahead
-             (funcall
-              parser-generator-lex-analyzer--function
-              index)))
-        (if next-look-ahead
-            (progn
-              (unless (listp (car next-look-ahead))
-                (setq next-look-ahead (list next-look-ahead)))
-              (dolist (next-look-ahead-item next-look-ahead)
-                (when (< look-ahead-length parser-generator--look-ahead-number)
-                  (push next-look-ahead-item look-ahead)
-                  (setq look-ahead-length (1+ look-ahead-length))
-                  (setq index (cdr (cdr next-look-ahead-item))))))
-          (push (list parser-generator--e-identifier) look-ahead)
-          (setq look-ahead-length (1+ look-ahead-length))
-          (setq index (1+ index)))))
+    (while (<
+            look-ahead-length
+            parser-generator--look-ahead-number)
+      (condition-case error
+          (progn
+            (let ((next-look-ahead
+                   (funcall
+                    parser-generator-lex-analyzer--function
+                    index)))
+              (if next-look-ahead
+                  (progn
+                    (unless (listp (car next-look-ahead))
+                      (setq next-look-ahead (list next-look-ahead)))
+                    (dolist (next-look-ahead-item next-look-ahead)
+                      (when (<
+                             look-ahead-length
+                             parser-generator--look-ahead-number)
+                        (push next-look-ahead-item look-ahead)
+                        (setq look-ahead-length (1+ look-ahead-length))
+                        (setq index (cdr (cdr next-look-ahead-item))))))
+                (push (list parser-generator--e-identifier) look-ahead)
+                (setq look-ahead-length (1+ look-ahead-length))
+                (setq index (1+ index)))))
+        (error (error
+                "Lex-analyze failed to peek next look-ahead at %s, error: %s"
+                index
+                (car (cdr error))))))
     (nreverse look-ahead)))
 
-;; TODO Catch errors
 (defun parser-generator-lex-analyzer--pop-token ()
   "Pop next token via lex-analyzer."
   (unless parser-generator-lex-analyzer--index
     (error "Missing lex-analyzer index!"))
   (unless parser-generator-lex-analyzer--function
     (error "Missing lex-analyzer function!"))
-  (let ((token (funcall
-                     parser-generator-lex-analyzer--function
-                     parser-generator-lex-analyzer--index)))
-    (unless (listp (car token))
-      (setq token (list token)))
-    (let ((first-token (car token)))
-      (setq parser-generator-lex-analyzer--index
-            (cdr (cdr first-token)))
-      first-token)))
+  (condition-case error
+      (progn
+        (let ((token (funcall
+                      parser-generator-lex-analyzer--function
+                      parser-generator-lex-analyzer--index)))
+          (unless (listp (car token))
+            (setq token (list token)))
+          (let ((first-token (car token)))
+            (setq parser-generator-lex-analyzer--index
+                  (cdr (cdr first-token)))
+            first-token)))
+    (error (error
+            "Lex-analyze failed to pop token at %s, error: %s"
+            parser-generator-lex-analyzer--index
+            (car (cdr error))))))
 
 (defun parser-generator-lex-analyzer--reset ()
   "Reset lex-analyzer."
diff --git a/test/parser-generator-lex-analyzer-test.el 
b/test/parser-generator-lex-analyzer-test.el
index 7666a57..e3fcc9c 100644
--- a/test/parser-generator-lex-analyzer-test.el
+++ b/test/parser-generator-lex-analyzer-test.el
@@ -26,11 +26,13 @@
      (let* ((string '(("a" 1 . 2) ("b" 2 . 3) ("c" 3 . 4) ("d" 4 . 5)))
             (string-length (length string))
             (max-index index)
-            (tokens))
+            (tokens)
+            (next-token))
        (while (and
                (< (1- index) string-length)
                (< (1- index) max-index))
-         (push (nth (1- index) string) tokens)
+         (setq next-token (nth (1- index) string))
+         (push next-token tokens)
          (setq index (1+ index)))
        (nreverse tokens))))
   (should-error
@@ -59,6 +61,27 @@
     '(("a" 1 . 2) ("b" 2 . 3) ("c" 3 . 4) ("d" 4 . 5) (e) (e) (e) (e) (e) (e))
     (parser-generator-lex-analyzer--peek-next-look-ahead)))
 
+  (setq
+   parser-generator-lex-analyzer--function
+   (lambda (index)
+     (let* ((string '(("a" 1 . 2) ("b" 2 . 3) ("c" 3 . 4) ("d" 4 . 5)))
+            (string-length (length string))
+            (max-index index)
+            (tokens)
+            (next-token))
+       (while (and
+               (< (1- index) string-length)
+               (< (1- index) max-index))
+         (setq next-token (nth (1- index) string))
+         (when (string= (car next-token) "d")
+           (error "Invalid token: %s" next-token))
+         (push next-token tokens)
+         (setq index (1+ index)))
+       (nreverse tokens))))
+
+  (should-error
+    (parser-generator-lex-analyzer--peek-next-look-ahead))
+
   (message "Ended tests for 
(parser-generator-lex-analyzer--peek-next-look-ahead)"))
 
 (defun parser-generator-lex-analyzer-test--pop-token ()