| # IBM AI4Code JSON-Graph Tools |
|
|
| ## Introduction |
|
|
| This is a collection of small utility programs written in C to manipulate |
| [IBM AI4Code JSON-Graph](../README.md) nodelist format files. |
| For now, 3 programs are offered: |
|
|
| 1. `jgf2dot` converts a graph or tree to the |
| [GraphViz dot input format](https://graphviz.org/doc/info/lang.html); and |
|
|
| 2. `jgf2spt` converts a tree (!) to the [Aroma SPT JSON](https://github.com/facebookresearch/aroma-paper-artifacts/blob/master/reference/data/example_query.json) format. |
|
|
| 3. `jsonml2jgf` accepts any JsonML as input and represents its tree structure |
| as a JSON-Graph. Alternatively, it can interpret the leaf nodes as tokens |
| and output those. |
|
|
| The programs use a [third-party JSON parser](https://github.com/zserge/jsmn) |
| that produces an array of tokens from an input character array. The expected |
| schema is hard-coded into the program logic. |
|
|
| ## Usage |
|
|
| ```bash |
| $ jgf2dot digraph.json > digraph.dot |
| |
| # or use in a pipe: |
| |
| $ cat digraph.json | jgf2dot > digraph.dot |
| |
| # or directly generate a PNG file: |
| |
| $ jgf2dot digraph.json | dot -Tpng > digraph.png |
| |
| # same for jgf2spt: |
| |
| $ jgf2spt tree.json > tree.spt |
| ``` |
|
|
| ## Restrictions |
|
|
| The input is assumed to be valid JSON and moreover must comply with the [IBM |
| AI4Code JSON-Graph schema](../graph-schema.json). |
| All checks immediately cause a program exit upon error. |
|
|
| Notice that the whole input will be loaded into memory before parsing starts. |
| The approach is to first construct a graph from the input and |
| afterwards traverse the graph to produce the output. |
| Here is an example JSON file: |
|
|
| ```json |
| { |
| "graph": { |
| "version": "1.0", |
| "directed": true, |
| "nodes": [ |
| { "id": "Node1" }, |
| { "id": "Node2" }, |
| { "id": "Node3" }, |
| { "id": "Node4" } |
| ], |
| "edges": [ |
| { "between": [ "Node1", "Node1" ] }, |
| { "between": [ "Node1", "Node2" ] }, |
| { "between": [ "Node1", "Node3" ] }, |
| { "between": [ "Node2", "Node4" ] }, |
| { "between": [ "Node3", "Node4" ] }, |
| { "between": [ "Node4", "Node3" ] }, |
| { "between": [ "Node4", "Node1" ] } |
| ] |
| } |
| } |
| ``` |
|
|
| The PNG image produced by dot via jgf2dot from this JSON input looks like |
| this: |
|
|
|  |
|
|
| ## Create parse tree and token stream with `srcML` |
|
|
| The `jsonml2jgf` utility reads a JsonML file. [JsonML](http://www.jsonml.org/) |
| is the JSON Markup Language meant to losslessly convert between XML and JSON. |
| Any XML document can hence be converted to JsonML and back without loss of |
| information. |
|
|
| [srcML](https://www.srcml.org) is a tool for the analysis of programming |
| language source code and it presents its results in the form of an XML |
| annotated source code. `srcML` supports the programming languages C, C++, C#, |
| and Java. |
|
|
| To convert XML to JsonML we use the |
| [`xml-to-jsonml`](https://github.com/bramstein/xsltjson/blob/master/conf/xml-to-jsonml.xsl) |
| XSLT script that can be processed with e.g. `xsltproc`. |
|
|
| Summarizing, the work flow looks as follows: |
|
|
| ```console |
| srcml --position source.c | xml-to-jsonml - | jsonml2jgf |
| ``` |
|
|
| The normal operation of `jsonml2jgf` is to produce a tree in JSON-Graph |
| format. The tree faithfully represents the structure of the JsonML input and |
| hence the structure of the XML elements (with associated attributes). |
| The tree can then be visualized via `jgf2dot` with GraphViz dot. |
|
|
| The program can be switched to output a token stream instead with the `-t` |
| command line option. The full option set is: |
|
|
| ```console |
| $ jsonml2jgf -h |
| Reads a JsonML file and constructs a JSON-Graph from its tree structure. |
| If the JsonML represents a (abstract) syntax tree, e.g. generated by scrML |
| then this program can also output a token stream instead. |
| |
| usage: jsonml2jgf [ -cdho:stvw ] [ FILE ] |
| |
| Command line options are: |
| -c : keep comments in the token output stream. |
| -d : print debug info to stderr; implies -v. |
| -h : print just this text to stderr and stop. |
| -o<file> : name for output file (instead of stdout). |
| -s : enable a special start token specifying the filename. |
| -t : output the tokens instead of a graph. |
| -v : print action summary to stderr. |
| -w : suppress all warning messages. |
| ``` |
|
|
| ### Example |
|
|
| Let's take the tools for a ride. Starting with a small C program, here are all |
| the intermediate and end results of the work flow: |
|
|
| ```C |
| // Fibonacci numbers. |
| int fib(int n) |
| { |
| return n < 2 ? n : fib(n-1) + fib(n-2); |
| } |
| ``` |
|
|
| The generated XML does not look pretty. It is easily beautified with `tidy |
| -xml -i -q`. |
|
|
| ```bash |
| $ srcml --position fib.c | tee fib.xml |
| <?xml version="1.0" encoding="UTF-8" standalone="yes"?> |
| <unit xmlns="http://www.srcML.org/srcML/src" xmlns:pos="http://www.srcML.org/srcML/position" revision="1.0.0" language="C" filename="fib.c" pos:tabs="8"><comment type="line" pos:start="1:1" pos:end="1:21">// Fibonacci numbers.</comment> |
| <function pos:start="2:1" pos:end="5:1"><type pos:start="2:1" pos:end="2:3"><name pos:start="2:1" pos:end="2:3">int</name></type> <name pos:start="2:5" pos:end="2:7">fib</name><parameter_list pos:start="2:8" pos:end="2:14">(<parameter pos:start="2:9" pos:end="2:13"><decl pos:start="2:9" pos:end="2:13"><type pos:start="2:9" pos:end="2:11"><name pos:start="2:9" pos:end="2:11">int</name></type> <name pos:start="2:13" pos:end="2:13">n</name></decl></parameter>)</parameter_list> |
| <block pos:start="3:1" pos:end="5:1">{<block_content pos:start="4:3" pos:end="4:41"> |
| <return pos:start="4:3" pos:end="4:41">return <expr pos:start="4:10" pos:end="4:40"><ternary pos:start="4:10" pos:end="4:40"><condition pos:start="4:10" pos:end="4:16"><expr pos:start="4:10" pos:end="4:14"><name pos:start="4:10" pos:end="4:10">n</name> <operator pos:start="4:12" pos:end="4:12"><</operator> <literal type="number" pos:start="4:14" pos:end="4:14">2</literal></expr> ?</condition><then pos:start="4:18" pos:end="4:18"> <expr pos:start="4:18" pos:end="4:18"><name pos:start="4:18" pos:end="4:18">n</name></expr> </then><else pos:start="4:20" pos:end="4:40">: <expr pos:start="4:22" pos:end="4:40"><call pos:start="4:22" pos:end="4:29"><name pos:start="4:22" pos:end="4:24">fib</name><argument_list pos:start="4:25" pos:end="4:29">(<argument pos:start="4:26" pos:end="4:28"><expr pos:start="4:26" pos:end="4:28"><name pos:start="4:26" pos:end="4:26">n</name><operator pos:start="4:27" pos:end="4:27">-</operator><literal type="number" pos:start="4:28" pos:end="4:28">1</literal></expr></argument>)</argument_list></call> <operator pos:start="4:31" pos:end="4:31">+</operator> <call pos:start="4:33" pos:end="4:40"><name pos:start="4:33" pos:end="4:35">fib</name><argument_list pos:start="4:36" pos:end="4:40">(<argument pos:start="4:37" pos:end="4:39"><expr pos:start="4:37" pos:end="4:39"><name pos:start="4:37" pos:end="4:37">n</name><operator pos:start="4:38" pos:end="4:38">-</operator><literal type="number" pos:start="4:39" pos:end="4:39">2</literal></expr></argument>)</argument_list></call></expr></else></ternary></expr>;</return> |
| </block_content>}</block></function> |
| </unit> |
| ``` |
|
|
| Next step, convert the XML to JsonML. Again, the output is unformatted JSON |
| and does not look great. If so desired run through `jq .` to get a |
| pretty-printed output. |
|
|
| ```bash |
| $ xml-to-jsonml fib.xml | tee fib.jsonml |
| ["unit",{"revision":"1.0.0","language":"C","filename":"fib.c","pos:tabs":8},["comment",{"type":"line","pos:start":"1:1","pos:end":"1:21"},"// Fibonacci numbers."],["function",{"pos:start":"2:1","pos:end":"5:1"},["type",{"pos:start":"2:1","pos:end":"2:3"},["name",{"pos:start":"2:1","pos:end":"2:3"},"int"]],["name",{"pos:start":"2:5","pos:end":"2:7"},"fib"],["parameter_list",{"pos:start":"2:8","pos:end":"2:14"},"(",["parameter",{"pos:start":"2:9","pos:end":"2:13"},["decl",{"pos:start":"2:9","pos:end":"2:13"},["type",{"pos:start":"2:9","pos:end":"2:11"},["name",{"pos:start":"2:9","pos:end":"2:11"},"int"]],["name",{"pos:start":"2:13","pos:end":"2:13"},"n"]]],")"],["block",{"pos:start":"3:1","pos:end":"5:1"},"{",["block_content",{"pos:start":"4:3","pos:end":"4:41"},["return",{"pos:start":"4:3","pos:end":"4:41"},"return ",["expr",{"pos:start":"4:10","pos:end":"4:40"},["ternary",{"pos:start":"4:10","pos:end":"4:40"},["condition",{"pos:start":"4:10","pos:end":"4:16"},["expr",{"pos:start":"4:10","pos:end":"4:14"},["name",{"pos:start":"4:10","pos:end":"4:10"},"n"],["operator",{"pos:start":"4:12","pos:end":"4:12"},"<"],["literal",{"type":"number","pos:start":"4:14","pos:end":"4:14"},2]]," |
| ?"],["then",{"pos:start":"4:18","pos:end":"4:18"},["expr",{"pos:start":"4:18","pos:end":"4:18"},["name",{"pos:start":"4:18","pos:end":"4:18"},"n"]]],["else",{"pos:start":"4:20","pos:end":"4:40"},": ",["expr",{"pos:start":"4:22","pos:end":"4:40"},["call",{"pos:start":"4:22","pos:end":"4:29"},["name",{"pos:start":"4:22","pos:end":"4:24"},"fib"],["argument_list",{"pos:start":"4:25","pos:end":"4:29"},"(",["argument",{"pos:start":"4:26","pos:end":"4:28"},["expr",{"pos:start":"4:26","pos:end":"4:28"},["name",{"pos:start":"4:26","pos:end":"4:26"},"n"],["operator",{"pos:start":"4:27","pos:end":"4:27"},"-"],["literal",{"type":"number","pos:start":"4:28","pos:end":"4:28"},1]]],")"]],["operator",{"pos:start":"4:31","pos:end":"4:31"},"+"],["call",{"pos:start":"4:33","pos:end":"4:40"},["name",{"pos:start":"4:33","pos:end":"4:35"},"fib"],["argument_list",{"pos:start":"4:36","pos:end":"4:40"},"(",["argument",{"pos:start":"4:37","pos:end":"4:39"},["expr",{"pos:start":"4:37","pos:end":"4:39"},["name",{"pos:start":"4:37","pos:end":"4:37"},"n"],["operator",{"pos:start":"4:38","pos:end":"4:38"},"-"],["literal",{"type":"number","pos:start":"4:39","pos:end":"4:39"},2]]],")"]]]]]],";"]],"}"]]] |
| ``` |
|
|
| Finally `jsonml2jgf` comes into play. Let's first get a nice picture of the |
| parse tree. We skip showing the intermediate JSON-Graph output which should be |
| well-known by now. |
|
|
| ```bash |
| $ jsonml2jgf fib.jsonml | jgf2dot | dot -Tpng -o fib.png |
| ``` |
|
|
|  |
|
|
| ### Token stream |
|
|
| The tokens of the input `fib.c` program are of course available as leaf nodes |
| in the parse tree. It is useful to have them (in order of occurrence of |
| course) as a separate output stream. For now there is a simple switch: use |
| `-t` to have the tokens output instead of the tree. |
|
|
| Finishing our example, here is a complete token stream for `fib.c` with |
| preprocessor directives and comments removed: |
|
|
| ```bash |
| $ jsonml2jgf -t fib.jsonml |
| 2,0,type,int |
| 2,4,function,fib |
| 2,7,operator,( |
| 2,8,type,int |
| 2,12,decl,n |
| 2,13,operator,) |
| 3,0,operator,{ |
| 4,2,keyword,return |
| 4,9,expr,n |
| 4,11,operator,< |
| 4,13,number,2 |
| 4,14,operator,? |
| 4,17,expr,n |
| 4,19,operator,: |
| 4,21,call,fib |
| 4,24,operator,( |
| 4,25,expr,n |
| 4,26,operator,- |
| 4,27,number,1 |
| 4,28,operator,) |
| 4,30,operator,+ |
| 4,32,call,fib |
| 4,35,operator,( |
| 4,36,expr,n |
| 4,37,operator,- |
| 4,38,number,2 |
| 4,39,operator,) |
| 4,39,keyword,; |
| 4,39,operator,} |
| ``` |
|
|
| Notice that lines are counted from 1 and columns from 0 (Emacs style). |
| This output is valid CSV, a header could be: |
|
|
| ```console |
| line,column,class,token |
| ``` |
|
|
| The possible token classes and their meaning are listed in the following |
| table. For now this is C oriented. For C++, Java and C# this has to be reviewed |
| and updated. |
|
|
| Class | Meaning | Example |
| ----------|---------|-------- |
| filename | this is optional; use `-s` | - |
| comment | this is optional; use `-c` | `/* A comment */` |
| keyword | reserved word | `while` |
| string | a double-quoted string literal | `"Hello"` |
| character | a single character literal | `'A'` |
| number | any integer or floating-point number | `0.31415e+1` |
| operator | any operator or punctuator symbol | `;` |
|
|
| Identifiers are used for many purposes and hence will be precisely classified |
| as to their role in the program: |
|
|
| Class | Purpose of identifier | Example |
| ---------|-----------------------|-------- |
| decl | variable declaration | `int`_`var`_`;` |
| name | variable usage | same as expr? |
| expr | variable usage | _`var`_`+ 1` |
| function | name definition | `void`_`fun`_`(int x)` |
| call | a function by name | _`fun`_`(3)` |
| typedef | name definition | `typedef int`_`MyInt`_`;` |
| type | usage of type name | _`MyInt`_`i;` |
| struct | name definition | `struct`_`Point`_`{}` |
| union | name definition | `union`_`Variant`_`{}` |
| enum | name definition | `enum`_`Color`_`{}` |
| label | name definition | _`target`_`:` |
| goto | label name | `goto`_`target`_`;` |
|
|
