just use Vector{UInt8} instead of raw pointer loads, since it's not clear we care about performance here

src/latex.jl

@@ -30,14 +30,14 @@ from the `arg`.
 function search_latexdirective(s::Union{String,SubString{String}}, istart::Int=1)
     e = sizeof(s)
     0 < istart ≤ e || return 0,0,0
-    p = pointer(s)
+    p = Vector{UInt8}(s)
     i = istart
     allspaces=true
 
     # find \foo directive or {...}:
     c = UInt8(0)
     while i ≤ e
-        c = unsafe_load(p, i)
+        c = p[i]
         (c == BACKSLASH || c == BRACEOPEN || c == CARET || c == UNDERSCORE) && break
         c != SPACE && (allspaces = false)
         i += 1
@@ -47,8 +47,8 @@ function search_latexdirective(s::Union{String,SubString{String}}, istart::Int=1
         if c == BACKSLASH
             i += 2
             i-1 > e && return 0,0,0
-            if isalpha8(unsafe_load(p, i-1))
-                while i ≤ e && isalpha8(unsafe_load(p, i))
+            if isalpha8(p[i-1])
+                while i ≤ e && isalpha8(p[i])
                     i += 1
                 end
             end
@@ -59,19 +59,19 @@ function search_latexdirective(s::Union{String,SubString{String}}, istart::Int=1
         end
 
         # look for optional opening brace
-        while i ≤ e && unsafe_load(p, i) == SPACE
+        while i ≤ e && p[i] == SPACE
             i += 1
         end
         i > e && return directive_start, directive_end, e
-        inbrace = unsafe_load(p, i) == BRACEOPEN
+        inbrace = p[i] == BRACEOPEN
         if !inbrace
             # search backwards from \foo to look for { \foo ...}
             j = directive_start - 1
-            while j ≥ istart && unsafe_load(p, j) == SPACE
+            while j ≥ istart && p[j] == SPACE
                 j -= 1
             end
-            if j < istart || unsafe_load(p, j) != BRACEOPEN
-                if unsafe_load(p, i) == BACKSLASH
+            if j < istart || p[j] != BRACEOPEN
+                if p[i] == BACKSLASH
                     # argument is another latex directive
                     ds,de,ae = search_latexdirective(s, i)
                     return directive_start, directive_end, ae
@@ -86,7 +86,7 @@ function search_latexdirective(s::Union{String,SubString{String}}, istart::Int=1
                     return directive_start, directive_end, e
                 else
                     # argument is not in braces … get next token
-                    while i ≤ e && isalnum8(unsafe_load(p, i))
+                    while i ≤ e && isalnum8(p[i])
                         i += 1
                     end
                     return directive_start, directive_end, i-1
@@ -106,7 +106,7 @@ function search_latexdirective(s::Union{String,SubString{String}}, istart::Int=1
     # search for end of argument (closing brace)
     nbraces = 1
     while i ≤ e
-        c = unsafe_load(p, i)
+        c = p[i]
         if c == BRACEOPEN
             nbraces += 1
         elseif c == BRACECLOSE
@@ -127,22 +127,23 @@ Return the substring of `s` corresponding to the argument from `argstart:argend`
 leading/trailing whitespace and braces.
 """
 function striparg(s::Union{String,SubString{String}}, argstart::Int=start(s), argend::Int=endof(s))
+    argstart > argend && return SubString(s, 1, 0)
     e = endof(s)
     (1 ≤ argstart ≤ e && 1 ≤ argend ≤ e) || throw(BoundsError())
 
-    p = pointer(s)
-    if unsafe_load(p, argend) == BRACECLOSE
+    p = Vector{UInt8}(s)
+    if p[argend] == BRACECLOSE
         argend -= 1 # omit brace
-        while argstart ≤ argend && unsafe_load(p, argstart) != BRACEOPEN
+        while argstart ≤ argend && p[argstart] != BRACEOPEN
             argstart += 1
         end
         argstart > argend && error("malformed argument")
         argstart += 1 # omit brace
     end
-    while argstart ≤ argend && unsafe_load(p, argend) == SPACE
+    while argstart ≤ argend && p[argend] == SPACE
         argend -= 1
     end
-    while argstart ≤ argend && unsafe_load(p, argstart) == SPACE
+    while argstart ≤ argend && p[argstart] == SPACE
         argstart += 1
     end
     return SubString(s, argstart, argend)
@@ -239,7 +240,7 @@ const superscripts = Dict{Char,Char}(
     'A'=>'ᴬ', 'B'=>'ᴮ', 'C'=>'ᶜ', 'D'=>'ᴰ', 'E'=>'ᴱ', 'G'=>'ᴳ', 'H'=>'ᴴ', 'I'=>'ᴵ', 'J'=>'ᴶ',
     'K'=>'ᴷ', 'L'=>'ᴸ', 'M'=>'ᴹ', 'N'=>'ᴺ', 'O'=>'ᴼ', 'P'=>'ᴾ', 'R'=>'ᴿ', 'S'=>'ˢ', 'T'=>'ᵀ',
     'U'=>'ᵁ', 'V'=>'ⱽ', 'W'=>'ᵂ', 'β'=>'ᵝ', 'γ'=>'ᵞ', 'δ'=>'ᵟ', 'ψ'=>'ᵠ', 'χ'=>'ᵡ', 'Θ'=>'ᶿ',
-    '+'=>'⁺', '-'=>'⁻', '='=>'⁼', '('=>'⁽', ')'=>'⁾', ' '=>' ',
+    '+'=>'⁺', '-'=>'⁻', '='=>'⁼', '('=>'⁽', ')'=>'⁾', ' '=>' ', '∘'=>'°',
 )
 const subscripts = Dict{Char,Char}(
     '0'=>'₀', '1'=>'₁', '2'=>'₂', '3'=>'₃', '4'=>'₄', '5'=>'₅', '6'=>'₆', '7'=>'₇', '8'=>'₈', '9'=>'₉',
@@ -296,10 +297,10 @@ replace_directives(s::AbstractString, extra_directives::Associative{String,Strin
 # strip unescaped $ signs from s
 function strip_dollars(s::Union{String,SubString{String}})
     buf = IOBuffer()
-    p = pointer(s)
+    p = Vector{UInt8}(s)
     for i = 1:sizeof(s)
-        c = unsafe_load(p, i)
-        if c == BACKSLASH && i < sizeof(s) && unsafe_load(p, i+1) == DOLLAR
+        c = p[i]
+        if c == BACKSLASH && i < sizeof(s) && p[i+1] == DOLLAR
             write(buf, DOLLAR) # \$ -> $
         elseif c != DOLLAR
             write(buf, c)