Support ${ # ## % %% }.

check.sh

@@ -69,6 +69,12 @@ tests="
 60-function
 60-subst
 
+70-hash.sh
+70-hash-hash.sh
+70-percent.sh
+70-percent-percent.sh
+70-percent-space.sh
+
 100-sed
 100-sed-once
 100-sed-global

gash/peg.scm

@@ -225,9 +225,13 @@
      dollar           <   '$'
      literal          <-- backslash? (!ws !amp !tick !dollar !pipe !semi !par !nl !sp !rbrace !io-op !dq !sq .)+
      variable         <-- dollar ('$' / '#' / '*' / '?' / '@' / [0-9] / identifier / lbrace identifier rbrace)
-     variable-and-or  <-  dollar lbrace (variable-or / variable-and ) rbrace
+     variable-and-or  <-  dollar lbrace (variable-or / variable-and / variable-hash-hash / variable-hash / variable-percent-percent / variable-percent ) rbrace
      variable-and     <-- identifier plus rhs
      variable-or      <-- identifier minus rhs
+     variable-hash    <-- identifier hash rhs
+     variable-hash-hash  <-- identifier hash hash rhs
+     variable-percent    <-- identifier percent rhs
+     variable-percent-percent  <-- identifier percent percent rhs
      delim            <-  singlequotes / doublequotes / substitution
      sq               <   [']
      dq               <   [\"]
@@ -248,6 +252,8 @@
      rbrace           <   [}]
      plus             <   [+]
      minus            <   '-'
+     hash             <   '#'
+     percent          <   '%'
      par              <   lpar / rpar
      nl               <   '\n'
      sp               <   '\t' / ' ' / (escaped-nl sp*)
@@ -351,19 +357,20 @@
 
     (('brace-group o) `(brace-group ,(transform o)))
     (('file-name o) `(file-name ,(transform o)))
+
     (_ ast)))
 
 
-(define (remove-shell-comments s)
+(define (remove-line-comments s)
   (string-join (map
                 (lambda (s)
-                  (let* ((n (string-index s #\#)))
-                    (if n (string-pad-right s (string-length s) #\space  0 n)
+                  (let ((n (string-index s #\#)))
+                    (if (and n (zero? n)) (string-pad-right s (string-length s) #\space  0 n)
                         s)))
                 (string-split s #\newline)) "\n"))
 
 (define (parse-string string)
-  (let* ((pt ((compose parse- remove-shell-comments) string))
+  (let* ((pt ((compose parse- remove-line-comments) string))
          (foo (when (> %debug-level 1) (display "tree:\n") (pretty-print pt)))
          (flat (flatten pt))
          (foo (when (> %debug-level 0) (display "flat:\n") (pretty-print flat)))

gash/script.scm

@@ -91,14 +91,16 @@
           (else (lambda () #t))))
   (exec (append-map glob args)))
 
-(define (glob pattern)
-  (define (glob? pattern)
-    (and (string? pattern) (string-match "\\?|\\*" pattern)))
-  (define (glob2regex pattern)
+(define (glob? pattern)
+  (and (string? pattern) (string-match "\\?|\\*" pattern)))
+
+(define* (glob->regex pattern #:key (begin "^") (end "$"))
     (let* ((pattern (regexp-substitute/global #f "\\." pattern 'pre "\\." 'post))
            (pattern (regexp-substitute/global #f "\\?" pattern 'pre "." 'post))
            (pattern (regexp-substitute/global #f "\\*" pattern 'pre ".*" 'post)))
-      (make-regexp (string-append "^" pattern "$"))))
+      (make-regexp (string-append begin pattern end))))
+
+(define (glob pattern)
   (define (glob-match regex path) ;; pattern path -> bool
     (regexp-match? (regexp-exec regex path)))
   (define (glob- pattern file-names)
@@ -107,7 +109,7 @@
          (append-map (lambda (file-name)
                        (map (cut string-append (if (string=? "/" file-name) "" file-name) "/" <>)
                             (filter (conjoin (negate (cut string-prefix? "." <>))
-                                             (cute glob-match (glob2regex pattern) <>))
+                                             (cute glob-match (glob->regex pattern) <>))
                                     (or (scandir file-name) '()))))
                      file-names)))
   (cond
@@ -285,3 +287,57 @@
 
 (define (file-name o)
   o)
+
+(define (regexp-exec-non-greedy regexp string)
+  (let ((max (string-length string)))
+    (let loop ((size 1))
+      (and (<= size max)
+           (or (regexp-exec regexp (substring string 0 size))
+               (loop (1+ size)))))))
+
+(define (regexp-exec-non-greedy-reverse regexp string)
+  (let ((max (string-length string)))
+    (let loop ((start (1- max)))
+      (and (>= start 0)
+           (or (regexp-exec regexp (substring string start))
+               (loop (1- start)))))))
+
+(define (variable-hash name pattern)
+  (let ((value (variable name))
+        (glob? (glob? pattern)))
+    (if glob? (let* ((regexp (glob->regex pattern #:end ""))
+                     (match (regexp-exec-non-greedy regexp value)))
+                (if match (string-drop value (match:end match))
+                    value))
+        (if (string-prefix? pattern value) (string-drop value (string-length pattern))
+            value))))
+
+(define (variable-hash-hash name pattern)
+  (let ((value (variable name))
+        (glob? (glob? pattern)))
+    (if glob? (let* ((regexp (glob->regex pattern #:end ""))
+                     (match (regexp-exec regexp value)))
+                (if match (string-drop value (match:end match))
+                    value))
+        (if (string-prefix? pattern value) (string-drop value (string-length pattern))
+            value))))
+
+(define (variable-percent name pattern)
+  (let ((value (variable name))
+        (glob? (glob? pattern)))
+    (if glob? (let* ((regexp (glob->regex pattern #:begin ""))
+                     (match (regexp-exec-non-greedy-reverse regexp value)))
+                (if match (substring value 0 (- (string-length value) (match:end match)))
+                    value))
+        (if (string-suffix? pattern value) (substring value 0 (string-length pattern))
+            value))))
+
+(define (variable-percent-percent name pattern)
+  (let ((value (variable name))
+        (glob? (glob? pattern)))
+    (if glob? (let* ((regexp (glob->regex pattern #:begin ""))
+                     (match (regexp-exec regexp value)))
+                (if match (substring value 0 (match:start match))
+                    value))
+        (if (string-suffix? pattern value) (substring value 0 (string-length pattern))
+            value))))

test/70-hash-hash.sh

@@ -0,0 +1,2 @@
+file=dir/sub/name.ext
+echo ${file##*/}

test/70-hash-hash.stdout

@@ -0,0 +1 @@
+name.ext

test/70-hash.sh

@@ -0,0 +1,2 @@
+file=dir/sub/name.ext
+echo ${file#*/}

test/70-hash.stdout

@@ -0,0 +1 @@
+sub/name.ext

test/70-percent-percent.sh

@@ -0,0 +1,2 @@
+file=dir/sub/name.ext
+echo ${file%%/*}

test/70-percent-percent.stdout

@@ -0,0 +1 @@
+dir

test/70-percent-space.sh

@@ -0,0 +1,2 @@
+args="--prefix=/usr "
+echo ${args% *}/

test/70-percent-space.stdout

@@ -0,0 +1 @@
+--prefix=/usr/

test/70-percent.sh

@@ -0,0 +1,2 @@
+file=dir/sub/name.ext
+echo ${file%/*}

test/70-percent.stdout

@@ -0,0 +1 @@
+dir/sub