branch: master
commit a06220cf36736dc206c07f77b646b03e9d02106c
Author: Junpeng Qiu <qjpchm...@gmail.com>
Commit: Junpeng Qiu <qjpchm...@gmail.com>
Update README
---
README.org | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/README.org b/README.org
index faa1805..97e9214 100644
--- a/README.org
+++ b/README.org
@@ -60,7 +60,8 @@ So we can
Note:
- =parsec-str= and =parsec-string= are different. =parsec-string= behaves the
same as =string= in Haskell, and =parsec-str= is more like combining
- =string= and =try= in Haskell.
+ =string= and =try= in Haskell. Personally I found =parsec-str= easier to
use
+ because =parsec-str= is "atomic", which is similar to =parsec-ch=.
- Use the power of regular expressions provided by =parsec-re= and simplify
the parser!
** Parser Combinators
@@ -151,7 +152,7 @@ So we can
(parsec-string "*/"))))
#+END_SRC
- THe equivalent Haskell program:
+ The following Haskell program does a similar thing:
#+BEGIN_SRC haskell
import Text.Parsec
@@ -263,6 +264,19 @@ So we can
least the error message could tell us some information. Yeah, not perfect but
usable.
+ To test whether a parser returns an error, use =parsec-error-p=. If it
returns
+ an error, you can use =parsec-error-str= to retrieve the error message as a
+ string.
+
+ You can decide what to do based on the return value of a parser:
+ #+BEGIN_SRC elisp
+ (let ((res (parsec-with-input "hello"
+ (parsec-str "world"))))
+ (if (parsec-error-p res)
+ (message "Parser failed:\n%s" (parsec-error-str res))
+ (message "Parser succeeded by returning %s" res)))
+ #+END_SRC
+
* Acknowledgement
- Daan Leijen for Haskell's Parsec
- [[https://github.com/jwiegley/][John Wiegley]] for
[[https://github.com/jwiegley/emacs-pl][emacs-pl]]
