| | 1 | (* L3 Compiler |
| | 2 | * Parse State System |
| | 3 | * Author: Kaustuv Chaudhuri <kaustuv+@cs.cmu.edu> |
| | 4 | * Annotations: Alex Vaynberg <alv@andrew.cmu.edu> |
| | 5 | * Modified: Frank Pfenning <fp@cs.cmu.edu> |
| | 6 | * |
| | 7 | * This tracks filename and newline characters |
| | 8 | * so character positions in lexer tokens |
| | 9 | * can be converted to line.column format for error messages |
| | 10 | *) |
| | 11 | |
| | 12 | signature PARSE_STATE = |
| | 13 | sig |
| | 14 | (* setfile(filename) sets current filename and resets newline positions *) |
| | 15 | val setfile : string -> unit |
| | 16 | |
| | 17 | (* newline(pos) adds pos to current newline positions *) |
| | 18 | val newline : int -> unit |
| | 19 | |
| | 20 | (* returns the current position information based on two integer offsets *) |
| | 21 | val ext : int * int -> Mark.ext option |
| | 22 | end |
| | 23 | |
| | 24 | structure ParseState :> PARSE_STATE = |
| | 25 | struct |
| | 26 | |
| | 27 | val currFilename = ref ""; |
| | 28 | val currLines = ref (nil : int list); |
| | 29 | |
| | 30 | fun setfile (filename) = |
| | 31 | (currFilename := filename; |
| | 32 | currLines := nil) |
| | 33 | |
| | 34 | fun newline pos = |
| | 35 | (currLines := pos :: !currLines) |
| | 36 | |
| | 37 | (* look (pos, newline_positions, line_number) = (line, col) |
| | 38 | * pos is buffer position |
| | 39 | * newline_positions is (reverse) list of newline positions in file |
| | 40 | * line_number is lenght of newline_positions |
| | 41 | *) |
| | 42 | fun look (pos, a :: rest, n) = |
| | 43 | (* a is end of line n *) |
| | 44 | if a < pos then (n+1, pos-a) |
| | 45 | else look (pos, rest, n-1) |
| | 46 | | look (pos, nil, n) = |
| | 47 | (* first line pos is off by 1 *) |
| | 48 | (1, pos-1) |
| | 49 | |
| | 50 | (* ext (leftpos, rightpos) = SOME((leftline, leftcol), (rightline, rightcol), filename) |
| | 51 | * return NONE for invalid position (0,0) |
| | 52 | *) |
| | 53 | fun ext (0, 0) = NONE |
| | 54 | | ext (left, right) = |
| | 55 | SOME (look (left, !currLines, List.length (!currLines)), |
| | 56 | look (right, !currLines, List.length (!currLines)), |
| | 57 | !currFilename) |
| | 58 | |
| | 59 | end |
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