| 1 | Implementation notes |
| 2 | -------------------- |
| 3 | |
| 4 | Files |
| 5 | ----- |
| 6 | |
| 7 | The library tex2any.lib contains the generic Latex parser. |
| 8 | It comprises tex2any.cc, tex2any.h and texutils.cc. |
| 9 | |
| 10 | The executable Tex2RTF is made up of tex2any.lib, |
| 11 | tex2rtf.cc (main driver and user interface), and specific |
| 12 | drivers for generating output: rtfutils.cc, htmlutil.cc |
| 13 | and xlputils.cc. |
| 14 | |
| 15 | Data structures |
| 16 | --------------- |
| 17 | |
| 18 | Class declarations are found in tex2any.h. |
| 19 | |
| 20 | TexMacroDef holds a macro (Latex command) definition: name, identifier, |
| 21 | number of arguments, whether it should be ignored, etc. Integer |
| 22 | identifiers are used for each Latex command for efficiency when |
| 23 | generating output. A hash table MacroDefs stores all the TexMacroDefs, |
| 24 | indexed on command name. |
| 25 | |
| 26 | Each unit of a Latex file is stored in a TexChunk. A TexChunk can be |
| 27 | a macro, argument or just a string: a TexChunk macro has child |
| 28 | chunks for the arguments, and each argument will have one or more |
| 29 | children for representing another command or a simple string. |
| 30 | |
| 31 | Parsing |
| 32 | ------- |
| 33 | |
| 34 | Parsing is relatively add hoc. read_a_line reads in a line at a time, |
| 35 | doing some processing for file commands (e.g. input, verbatiminclude). |
| 36 | File handles are stored in a stack so file input commands may be nested. |
| 37 | |
| 38 | ParseArg parses an argument (which might be the whole Latex input, |
| 39 | which is treated as an argument) or a single command, or a command |
| 40 | argument. The parsing gets a little hairy because an environment, |
| 41 | a normal command and bracketed commands (e.g. {\bf thing}) all get |
| 42 | parsed into the same format. An environment, for example, |
| 43 | is usually a one-argument command, as is {\bf thing}. It also |
| 44 | deals with user-defined macros. |
| 45 | |
| 46 | Whilst parsing, the function MatchMacro gets called to |
| 47 | attempt to find a command following a backslash (or the |
| 48 | start of an environment). ParseMacroBody parses the |
| 49 | arguments of a command when one is found. |
| 50 | |
| 51 | Generation |
| 52 | ---------- |
| 53 | |
| 54 | The upshot of parsing is a hierarchy of TexChunks. |
| 55 | TraverseFromDocument calls the recursive TraverseFromChunk, |
| 56 | and is called by the 'client' converter application to |
| 57 | start the generation process. TraverseFromChunk |
| 58 | calls the two functions OnMacro and OnArgument, |
| 59 | twice for each chunk to allow for preprocessing |
| 60 | and postprocessing of each macro or argument. |
| 61 | |
| 62 | The client defines OnMacro and OnArgument to test |
| 63 | the command identifier, and output the appropriate |
| 64 | code. To help do this, the function TexOutput |
| 65 | outputs to the current stream(s), and |
| 66 | SetCurrentOutput(s) allows the setting of one |
| 67 | or two output streams for the output to be sent to. |
| 68 | Usually two outputs at a time are sufficient for |
| 69 | hypertext applications where a title is likely |
| 70 | to appear in an index and as a section header. |
| 71 | |
| 72 | There are support functions for getting the string |
| 73 | data for the current chunk (GetArgData) and the |
| 74 | current chunk (GetArgChunk). If you have a handle |
| 75 | on a chunk, you can output it several times by calling |
| 76 | TraverseChildrenFromChunk (not TraverseFromChunk because |
| 77 | that causes infinite recursion). |
| 78 | |
| 79 | The client (here, Tex2RTF) also defines OnError and OnInform output |
| 80 | functions appropriate to the desired user interface. |
| 81 | |
| 82 | References |
| 83 | ---------- |
| 84 | |
| 85 | Adding, finding and resolving references are supported |
| 86 | with functions from texutils.cc. WriteTexReferences |
| 87 | and ReadTexReferences allow saving and reading references |
| 88 | between conversion processes, rather like real LaTeX. |
| 89 | |
| 90 | Bibliography |
| 91 | ------------ |
| 92 | |
| 93 | Again texutils.cc provides functions for reading in .bib files and |
| 94 | resolving references. The function OutputBibItem gives a generic way |
| 95 | outputting bibliography items, by 'faking' calls to OnMacro and |
| 96 | OnArgument, allowing the existing low-level client code to take care of |
| 97 | formatting. |
| 98 | |
| 99 | Units |
| 100 | ----- |
| 101 | |
| 102 | Unit parsing code is in texutils.cc as ParseUnitArgument. It converts |
| 103 | units to points. |
| 104 | |
| 105 | Common errors |
| 106 | ------------- |
| 107 | |
| 108 | 1) Macro not found: \end{center} ... |
| 109 | |
| 110 | Rewrite: |
| 111 | |
| 112 | \begin{center} |
| 113 | {\large{\underline{A}}} |
| 114 | \end{center} |
| 115 | |
| 116 | as: |
| 117 | |
| 118 | \begin{center} |
| 119 | {\large \underline{A}} |
| 120 | \end{center} |
| 121 | |
| 122 | 2) Tables crash RTF. Set 'compatibility ' to TRUE in .ini file; also |
| 123 | check for \\ end of row characters on their own on a line, insert |
| 124 | correct number of ampersands for the number of columns. E.g. |
| 125 | |
| 126 | hello & world\\ |
| 127 | \\ |
| 128 | |
| 129 | becomes |
| 130 | |
| 131 | hello & world\\ |
| 132 | &\\ |
| 133 | |
| 134 | 3) If list items indent erratically, try increasing |
| 135 | listItemIndent to give more space between label and following text. |
| 136 | A global replace of '\item [' to '\item[' may also be helpful to remove |
| 137 | unnecessary space before the item label. |
| 138 | |
| 139 | 4) Missing figure or section references: ensure all labels _directly_ follow captions |
| 140 | or sections (no intervening white space). |