Perfomance Improvments for definition

src/CodeTracking.jl

@@ -245,36 +245,40 @@ function definition(::Type{String}, method::Method)
     # Step forward to the definition of this method, keeping track of positions of newlines
     # Issue: in-code `'\n'`. To fix, presumably we'd have to parse the entire file.
     eol = isequal('\n')
-    linestarts = Int[]
+    slop = 20
+    linestarts = zeros(Int, slop)
     istart = 1
-    for _ = 1:line-1
-        push!(linestarts, istart)
+    lineindex = 1
+    for i in 1:line-1
+        if i > line - slop
+            linestarts[lineindex] = istart
+            lineindex += 1
+        end
         istart = findnext(eol, src, istart) + 1
     end
-    push!(linestarts, length(src) + 1)
-    # Parse the function definition (hoping that we've found the right location to start)
-    ex, iend = Meta.parse(src, istart; raise=false)
+    linestarts[lineindex] = istart
     # The function declaration may have been on a previous line,
     # allow some slop
-    lineindex = lastindex(linestarts)
-    linestop = max(0, lineindex - 20)
-    while !is_func_expr(ex, method) && lineindex > linestop
-        if isexpr(ex, :call) && length(ex.args) > 1 && first(ex.args) == :eval && isexpr(last(ex.args), :quote) && length(last(ex.args).args) > 0
-            actual_ex = first(last(ex.args).args)
-            if is_func_expr(actual_ex, method)
-                return clean_source(string(actual_ex)), line
-            end
-        end
+    while lineindex > 0
         istart = linestarts[lineindex]
-        try
-            ex, iend = Meta.parse(src, istart)
+        # Parse the function definition (hoping that we've found the right location to start)
+        ex, iend = try
+            Meta.parse(src, istart)
         catch
+            nothing, nothing
+        end
+
+        is_func_expr(ex, method) && return clean_source(src[istart:prevind(src, iend)]), line
+
+        if isexpr(ex, :call) && length(ex.args) > 1 && first(ex.args) == :eval && isexpr(last(ex.args), :quote) && length(last(ex.args).args) > 0
+            ex = first(last(ex.args).args)
+            is_func_expr(ex, method) && return clean_source(string(ex)), line
         end
+
         lineindex -= 1
         line -= 1
     end
-    lineindex <= linestop && return nothing
-    return clean_source(src[istart:prevind(src, iend)]), line
+    return nothing
 end
 
 function clean_source(src)