EAL V2.0 by Douglas W. Jones; Wed Jun 30 15:01:11 2004

     1             |; test2.a
     2             |;   test EAL version MP2
     3             |
     4             |;   Date:    June 29, 2004
     5             |;   Author:  Douglas Jones
     6             |
     7             |; demo of types of <operand> largely lifted from HW3
     8             |
     9             |IDENT = 1     ; an identifier for demo purposes
    10             |
    11             |; forms of terms, note that <operand> ::= <sub expr>
    12             |;                  and that <sub expr> ::= <term>
    13 0000: 0001  |      W IDENT           ; <term> ::= <identifier>
    14 0002: 0063  |      W 99              ; <term> ::= <number>
    15 0004: 0004  |      W .               ; <term> ::= .
    16             |
    17             |; forms of subexpressions, note that <term> ::= IDENT
    18 0006: 0001  |      W IDENT           ; <sub expr> ::= <term>
    19 0008: 0002  |      W IDENT + IDENT   ; <sub expr> ::= <term> { + <term> }
    20 000A: 0003  |      W IDENT + IDENT + IDENT
    21 000C: 0004  |      W IDENT + IDENT + IDENT + IDENT
    22             |
    23             |; permissible operators in subexpressions
    24 000E: 0002  |      W IDENT + IDENT   ; ::= <term> { (+|-|&||) <term> }
    25 0010: 0000  |      W IDENT - IDENT
    26 0012: 0001  |      W 99 & IDENT      ; note, 99 and 1 is 1
    27 0014: 0063  |      W 99 | IDENT      ; note, 99 or 1 is 99
    28             |
    29             |; parentheses (not in the BNF, but in parse_operand)!
    30 0016: 0001  |      W (IDENT)
    31 0018: 0002  |      W IDENT + (IDENT)
    32 001A: 0002  |      W (IDENT) + IDENT
    33 001C: 0002  |      W (IDENT + IDENT)
    34             |
    35             |; some illustrations of operator precidence and parens
    36 001E: 0005  |      W    1 + 2 - 3 & 4 | 5    ; = 5
    37 0020: 0005  |      W (((1 + 2)- 3)& 4)| 5    ; = 5
    38 0022: 0002  |      W    1 +(2 -(3 &(4 | 5))) ; = 2
    39 0024: 0002  |      W   (1 + 2)-(3 &(4 | 5))  ; = 2
    40 0026: 0000  |      W  ((1 + 2)- 3)&(4 | 5)   ; = 0
    41             |
    42             |; test <operand> ::= <sub expr> [ = <sub expr> ]
    43 0028: FFFF  |      W  IDENT    =  IDENT      ; true  = FFFF
    44 002A: 0000  |      W  IDENT    = (IDENT+1)   ; false = 0000
    45 002C: 0000  |      W (IDENT+1) =  IDENT      ; false = 0000
    46 002E: FFFF  |      W (IDENT+1) = (IDENT+1)   ; true  = FFFF
    47             |
    48             |; test operator precidence for subexpressions
    49 0030: 0000  |      W  IDENT    =  IDENT+1    ; false = 0000
    50 0032: 0000  |      W  IDENT+1  =  IDENT      ; false = 0000
    51 0034: FFFF  |      W  IDENT+1  =  IDENT+1    ; true  = FFFF
    52 0036: 0001  |      W (IDENT+1  =  IDENT)+1   ; gives 1 (not Boolean)
    53 0038: 0001  |      W  IDENT+(1 =  IDENT)+1   ; gives 1 (not Boolean)
    54             |
    55             |; demonstrate precidence with other operators
    56 003A: FFFF  |      W  IDENT&3  =  IDENT&5    ; true  = FFFF
    57 003C: 0000  |      W  IDENT&4  =  IDENT&5    ; false = 0000
    58 003E: FFFF  |      W  IDENT|4  =  IDENT|5    ; true  = FFFF
    59 0040: 0000  |      W  IDENT|3  =  IDENT|5    ; false = 0000
    60             |
    61             |; contexts for operands
    62 0042: 02    |      B IDENT + 1
    63 0043: 0003  |      W IDENT + 2
    64             |IDENT = IDENT + 3
    65             |
    66             |; errors involving undefined operands
    67 0045: ??    |      B UNDEFINED
                            ^
undefined
    68 0046: ??    |      B UNDEFINED + IDENT
                            ^
undefined
    69 0047: ??    |      B IDENT + UNDEFINED
                                    ^
undefined
    70 0048: ??    |      B UNDEFINED = IDENT
                            ^
undefined
    71 0049: ??    |      B IDENT = UNDEFINED
                                    ^
undefined
    72             |
    73             |; error involving syntax
    74 004A: ??    |      B (
                             ^
operand expected
    75 004B: 04    |      B (IDENT
                                  ^
end paren expected
    76 004C: ??    |      B  IDENT +
                                    ^
operand expected
    77 004D: ??    |      B (IDENT +
                                    ^
operand expected
    78 004E: ??    |      B  IDENT =
                                    ^
operand expected
    79 004F: ??    |      B (IDENT = 
                                    ^
operand expected
    80 0050: 04    |      B  IDENT)
                                  ^
comment expected
    81 0051: ??    |      B )
                            ^
operand expected
    82 0052: ??    |      B )
                            ^
operand expected
    83             |