Merge pull request #11815 from JuliaLang/mn/kill@mstr

move triple-quoted string processing into parser

NEWS.md

@@ -125,6 +125,9 @@ Language changes
   * The keyword `local` is no longer allowed in global scope. Use `let` instead of
     `begin` to create a new scope from the top level ([#7234], [#10472]).
 
+  * Triple-quoted strings no longer treat tabs as 8 spaces. Instead, the
+    longest common prefix of spaces and tabs is removed.
+
 Command line option changes
 ---------------------------
 

base/docs/Docs.jl

@@ -156,8 +156,6 @@ namify(sy::Symbol) = sy
 function mdify(ex)
     if isa(ex, AbstractString)
         :(@doc_str $ex)
-    elseif isexpr(ex, :macrocall) && namify(ex) == symbol("@mstr")
-        :(@doc_str $(Expr(:triple_quoted_string, ex.args[2])))
     else
         esc(ex)
     end

base/exports.jl

@@ -1329,7 +1329,6 @@ export
     @int128_str,
     @uint128_str,
     @big_str,
-    @mstr,   # triple-quoted strings
     @cmd,    # `commands`
 
     # notation for certain types

base/string.jl

@@ -1050,51 +1050,10 @@ function unindent(s::AbstractString, indent::Int)
     takebuf_string(buf)
 end
 
-function triplequoted(args...)
-    sx = Any[ isa(arg,ByteString) ? arg : esc(arg) for arg in args ]
-
-    indent = 0
-    rlines = split(RevString(sx[end]), '\n'; limit=2)
-    last_line = rlines[1]
-    if length(rlines) > 1 && lstrip(last_line) == ""
-        indent,_ = indentation(last_line)
-    else
-        indent = typemax(Int)
-        for s in sx
-            if isa(s,ByteString)
-                lines = split(s,'\n')
-                for line in lines[2:end]
-                    n,blank = indentation(line)
-                    if !blank
-                        indent = min(indent, n)
-                    end
-                end
-            end
-        end
-    end
-
-    for i in 1:length(sx)
-        if isa(sx[i],ByteString)
-            sx[i] = unindent(sx[i], indent)
-        end
-    end
-
-    # strip leading blank line
-    s = sx[1]
-    j = search(s,'\n')
-    if j != 0 && lstrip(s[1:j]) == ""
-        sx[1] = s[j+1:end]
-    end
-
-    length(sx) == 1 ? sx[1] : Expr(:call, :string, sx...)
-end
-
 ## core string macros ##
 
 macro b_str(s); :($(unescape_string(s)).data); end
 
-macro mstr(s...); triplequoted(s...); end
-
 ## shell-like command parsing ##
 
 function shell_parse(raw::AbstractString, interp::Bool)

contrib/BBEditTextWrangler-julia.plist

@@ -106,14 +106,12 @@
               <string>@less</string>
               <string>@linux</string>
               <string>@linux_only</string>
-              <string>@mstr</string>
               <string>@non_windowsxp_only</string>
               <string>@osx</string>
               <string>@osx_only</string>
               <string>@parallel</string>
               <string>@printf</string>
               <string>@profile</string>
-              <string>@r_mstr</string>
               <string>@r_str</string>
               <string>@schedule</string>
               <string>@show</string>

src/julia-parser.scm

@@ -1027,7 +1027,7 @@
                                     (parse-string-literal s #t)))
                         (nxt (peek-token s))
                         (macname (symbol (string #\@ ex '_str)))
-                        (macstr (if (triplequote-string-literal? str) str (cadr str))))
+                        (macstr (car str)))
                    (if (and (symbol? nxt) (not (operator? nxt))
                             (not (ts:space? s)))
                        ;; string literal suffix, "s"x
@@ -1634,9 +1634,89 @@
   (let ((p (ts:port s)))
     (if (eqv? (peek-char p) #\")
         (if (eqv? (peek-char (take-char p)) #\")
-            (parse-string-literal- 'triple_quoted_string 2 (take-char p) s custom)
-            '(single_quoted_string ""))
-        (parse-string-literal- 'single_quoted_string 0 p s custom))))
+            (strip-first-newline
+              (dedent-triplequoted-string
+                (parse-string-literal- 2 (take-char p) s custom)))
+            (list ""))
+        (parse-string-literal- 0 p s custom))))
+
+(define (strip-first-newline lst)
+  (let* ((f (car lst))
+         (n (sizeof f)))
+    (if (and (> n 0) (eqv? (string.char f 0) #\newline))
+        (cons (string.sub f 1 n) (cdr lst))
+        lst)))
+
+(define (dedent-triplequoted-string lst)
+  (let ((prefix (triplequoted-string-indentation lst)))
+    (if (length> prefix 0)
+        (map (lambda (s)
+               (if (string? s)
+                   (string-swap s
+                                (list->string (cons #\newline prefix))
+                                #\newline)
+                   s))
+             lst)
+        lst)))
+
+(define (triplequoted-string-indentation lst)
+  (longest-common-prefix
+    (apply append (map (lambda (s) (if (string? s)
+                                       (triplequoted-string-indentation- s)
+                                       ()))
+                       lst))))
+
+(define (triplequoted-string-indentation- s)
+  (let ((p (open-input-string s)))
+    (let loop ((c (read-char p))
+               (state 0)
+               (prefix ())
+               (prefixes ()))
+      (cond
+        ((eqv? c #\newline)
+         (loop (read-char p) 1 () prefixes))
+        ((eqv? state 0)
+         (if (eof-object? c) prefixes
+             (loop (read-char p) 0 () prefixes)))
+        ((memv c '(#\space #\tab))
+         (loop (read-char p) 2 (cons c prefix) prefixes))
+        (else
+         (loop (read-char p) 0 () (cons (reverse prefix) prefixes)))))))
+
+; return the longest common prefix of the elements of l
+; e.g., (longest-common-prefix ((1 2) (1 4))) -> (1)
+(define (longest-common-prefix l)
+  (let ((len (length l)))
+  (cond
+    ((= len 0) ())
+    ((= len 1) (car l))
+    (else (longest-common-prefix
+            (cons (longest-common-prefix2 (car l) (cadr l))
+                  (cddr l)))))))
+
+; return the longest common prefix of lists a & b
+(define (longest-common-prefix2 a b)
+  (longest-common-prefix2- a b ()))
+
+(define (longest-common-prefix2- a b p)
+  (if (and (length> a 0)
+           (length> b 0)
+           (eqv? (car a) (car b)))
+      (longest-common-prefix2- (cdr a) (cdr b) (cons (car a) p))
+      (reverse p)))
+
+(define (string-split s sep)
+  (string-split- s sep 0 ()))
+
+(define (string-split- s sep start splits)
+  (let ((i (string.find s sep start)))
+    (if i
+        (string-split- s sep (+ i (sizeof sep)) (cons (string.sub s start i) splits))
+        (reverse (cons (string.sub s start (sizeof s)) splits)))))
+
+; swap all occurrences of a in s with b
+(define (string-swap s a b)
+  (string.join (string-split s a) b))
 
 (define (parse-interpolate s)
   (let* ((p (ts:port s))
@@ -1664,10 +1744,10 @@
 ;; custom = custom string literal
 ;; when custom is #t, unescape only \\ and \"
 ;; otherwise do full unescaping, and parse interpolations too
-(define (parse-string-literal- head n p s custom)
+(define (parse-string-literal- n p s custom)
   (let loop ((c (read-char p))
              (b (open-output-string))
-             (e (list head))
+             (e ())
              (quotes 0))
     (cond
       ((eqv? c #\")
@@ -1706,9 +1786,6 @@
        (write-char (not-eof-3 c) b)
        (loop (read-char p) b e 0)))))
 
-(define (interpolate-string-literal? s) (length> s 2))
-(define (triplequote-string-literal? s) (eqv? (car s) 'triple_quoted_string))
-
 (define (not-eof-1 c)
   (if (eof-object? c)
       (error "incomplete: invalid character literal") ; NOTE: changing this may affect code in base/client.jl
@@ -1897,14 +1974,12 @@
           ((eqv? t #\")
            (take-token s)
            (let ((ps (parse-string-literal s #f)))
-             (if (triplequote-string-literal? ps)
-                 `(macrocall @mstr ,@(cdr ps))
-                 (if (interpolate-string-literal? ps)
-                     `(string ,@(filter (lambda (s)
-                                          (not (and (string? s)
-                                                    (= (length s) 0))))
-                                        (cdr ps)))
-                     (cadr ps)))))
+             (if (length> ps 1)
+                 `(string ,@(filter (lambda (s)
+                                      (not (and (string? s)
+                                                (= (length s) 0))))
+                                    ps))
+                 (car ps))))
 
           ;; macro call
           ((eqv? t #\@)

src/julia-syntax.scm

@@ -3310,14 +3310,7 @@ So far only the second case can actually occur.
          e)
         ((eq? (car e) 'macrocall)
          ;; expand macro
-         (let ((form
-		(if (and (length> e 2) (pair? (caddr e)) (eq? (caaddr e) 'triple_quoted_string))
-		    ;; for a custom triple-quoted string literal, first invoke mstr
-		    ;; to handle unindenting
-		    (apply invoke-julia-macro (cadr e)
-			   (julia-expand-macros `(macrocall @mstr ,(cadr (caddr e))))
-			   (cdddr e))
-		    (apply invoke-julia-macro (cadr e) (cddr e)))))
+         (let ((form (apply invoke-julia-macro (cadr e) (cddr e))))
            (if (not form)
                (error (string "macro \"" (cadr e) "\" not defined")))
            (if (and (pair? form) (eq? (car form) 'error))

test/strings.jl

@@ -910,14 +910,14 @@ nl = "
       a
      b
        c""" == " a$(nl)b$(nl)  c"
-# note tab/space mixing
+# tabs + spaces
 @test """
-	a
-     b
-     """ == "   a$(nl)b$(nl)"
+	 a
+	 b
+	""" == " a$(nl) b$(nl)"
 @test """
       a
-       """ == "a$(nl)"
+       """ == "a$(nl) "
 s = "   p"
 @test """
       $s""" == "$s"
@@ -937,10 +937,6 @@ s = "   p"
 @test """
       foo
       bar\t""" == "foo$(nl)bar\t"
-@test """
-      foo
-      \tbar
-       """ == "foo$(nl)       bar$(nl)"
 
 # bytes2hex and hex2bytes
 hex_str = "d7a8fbb307d7809469ca9abcb0082e4f8d5651e46d3cdb762d02d0bf37c9e592"