Improve indicator performance

Author: omus

src/BlockScalars.jl

@@ -2,43 +2,46 @@ module BlockScalars
 
 export @blk_str
 
-const DEFAULT_BLOCK_SCALAR = "fs"
 
-function block(str::AbstractString, block_scalar::AbstractString=DEFAULT_BLOCK_SCALAR)
-    style_indicators = intersect(block_scalar, "fl")
-    chomp_indicators = intersect(block_scalar, "csk")
-
-    if length(style_indicators) == 0
-        style_indicator = 'f'
-    elseif length(style_indicators) == 1
-        style_indicator = first(style_indicators)
-    else
-        throw(ArgumentError("Only one block style indicators can be provided"))
-    end
-
-    if length(chomp_indicators) == 0
-        chomp_indicator = 's'
-    elseif length(chomp_indicators) == 1
-        chomp_indicator = first(chomp_indicators)
+const DEFAULT_STYLE = 'f'
+const DEFAULT_CHOMP = 's'
+
+function block(str::AbstractString, block_scalar::AbstractString="")
+    block_scalar_len = length(block_scalar)
+    block_scalar_len > 2 && throw(ArgumentError("Too many indicators provided"))
+
+    style, chomp = if block_scalar_len == 2
+        block_scalar
+    elseif block_scalar_len == 1
+        ind = block_scalar[1]
+        if ind in "fl"
+            ind, DEFAULT_CHOMP
+        else
+            DEFAULT_STYLE, ind
+        end
     else
-        throw(ArgumentError("Only one block chomp indicators can be provided"))
+        DEFAULT_STYLE, DEFAULT_CHOMP
     end
 
-    if style_indicator == 'f'
+    if style == 'f'
         str = replace(str, r"(?<=\S)\n(?=\S)" => " ")
         str = replace(str, r"(?<=\S)\n(\n+)(?!$)" => s"\1")
+    elseif style != 'l'
+        throw(ArgumentError("Unknown block style indicator: $(repr(style))"))
     end
 
-    if chomp_indicator == 'c'
+    if chomp == 'c'
         str = replace(str, r"\n+$" => "\n")
-    elseif chomp_indicator == 's'
+    elseif chomp == 's'
         str = replace(str, r"\n+$" => "")
+    elseif chomp != 'k'
+        throw(ArgumentError("Unknown block chomping indicator: $(repr(chomp))"))
     end
 
     return str
 end
 
-macro blk_str(str::AbstractString, suffix::AbstractString=DEFAULT_BLOCK_SCALAR)
+macro blk_str(str::AbstractString, suffix::AbstractString="")
     block(str, suffix)
 end
 

test/runtests.jl

@@ -56,4 +56,12 @@ const WHITESPACE = "a\nb\n c \nd\n"
             @test block(str) == yaml_block(str, ">-")
         end
     end
+
+    @testset "block invalid indicator" begin
+        @test_throws ArgumentError block("", "fs_")  # Too many indicators
+        @test_throws ArgumentError block("", "sf")   # Order matters
+        @test_throws ArgumentError block("", "_s")   # Invalid style
+        @test_throws ArgumentError block("", "f_")   # Invalid chomp
+        @test_throws ArgumentError block("", "_")    # Invalid style/chomp
+    end
 end