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Optimize the lexical scanner a little

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This commit is contained in:
David Schmenk 2014-12-10 20:20:11 -08:00
parent 30bc5c175d
commit 9b056aed69
1 changed files with 101 additions and 105 deletions
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206
src/toolsrc/sb.pla
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@ -129,7 +129,7 @@ const SUB_TKN = $AD // -
const MUL_TKN = $AA // *
const DIV_TKN = $AF // /
const MOD_TKN = $A5 // %
const OR_TKN = $BF // ?
const OR_TKN = $FC // |
const EOR_TKN = $DE // ^
const AND_TKN = $A6 // &
const SHR_TKN = $D2 // R
@ -150,7 +150,7 @@ const DOT_TKN = $AE // .
const COLON_TKN = $BA // :
const NEG_TKN = $AD // -
const COMP_TKN = $A3 // #
const LOGIC_NOT_TKN = $A1 // !
const LOGIC_NOT_TKN = $FE // ~
const BPTR_TKN = $DE // ^
const WPTR_TKN = $AA // *
const PTRB_TKN = $D8 // X
@ -317,7 +317,7 @@ byte lastop = $FF
const inbuff = $0200
const instr = $01FF
word scanptr = @nullstr
byte token, tknlen
byte scanchr, token, tknlen
byte parserrpos, parserr = 0
word tknptr, parserrln
word constval
@ -2630,15 +2630,16 @@ def scan
while ^scanptr == ' '
scanptr = scanptr + 1
loop
tknptr = scanptr
tknptr = scanptr
scanchr = ^scanptr
//
// Scan for token based on first character
//
if !^scanptr or ^scanptr == ';'
if !scanchr or scanchr == ';'
if token <> EOF_TKN
token = EOL_TKN
fin
elsif isalpha(^scanptr)
elsif isalpha(scanchr)
//
// ID, either variable name or reserved word
//
@ -2647,7 +2648,7 @@ def scan
until !isalphanum(^scanptr)
tknlen = scanptr - tknptr
token = keymatch
elsif isnum(^scanptr)
elsif isnum(scanchr)
//
// Decimal constant
//
@ -2657,71 +2658,42 @@ def scan
constval = constval * 10 + ^scanptr - '0'
scanptr = scanptr + 1
until !isnum(^scanptr)
elsif ^scanptr == '$'
//
// Hexadecimal constant
//
token = INT_TKN
constval = 0
repeat
scanptr = scanptr + 1
if ^scanptr >= '0' and ^scanptr <= '9'
constval = (constval << 4) + ^scanptr - '0'
elsif ^scanptr >= 'A' and ^scanptr <= 'F'
constval = (constval << 4) + ^scanptr - '7'// 'A'-10
elsif ^scanptr >= 'a' and ^scanptr <= 'f'
constval = (constval << 4) + ^scanptr - 'W'// 'a'-10
else
break
fin
until !^scanptr
elsif ^scanptr == $27 // '
//
// Character constant
//
token = CHR_TKN
if ^(scanptr + 1) <> $5C // \
constval = ^(scanptr + 1)
if ^(scanptr + 2) <> $27 // '
return parse_err(@bad_cnst)
fin
scanptr = scanptr + 3
else
when ^(scanptr + 2)
is 'n'
constval = $0D; break
is 'r'
constval = $0A; break
is 't'
constval = $09; break
otherwise
constval = ^(scanptr + 2)
wend
if ^(scanptr + 3) <> $27 // '
return parse_err(@bad_cnst)
fin
scanptr = scanptr + 4
fin
elsif ^scanptr == '"'
//
// String constant
//
token = STR_TKN
scanptr = scanptr + 1
constval = scanptr
while ^scanptr and ^scanptr <> '"'
scanptr = scanptr + 1
loop
if !^scanptr
return parse_err(@bad_cnst)
fin
scanptr = scanptr + 1
else
//
// Potential two and three character tokens
// Potential multiple character tokens
//
when ^scanptr
is '>'
when scanchr
is '/'
if ^(scanptr + 1) == '/'
token = EOL_TKN
^scanptr = $00
else
token = DIV_TKN
scanptr = scanptr + 1
fin
break
is '='
if ^(scanptr + 1) == '='
token = EQ_TKN
scanptr = scanptr + 2
elsif ^(scanptr + 1) == '>'
token = PTRW_TKN
scanptr = scanptr + 2
else
token = SET_TKN
scanptr = scanptr + 1
fin
break
is '-'
if ^(scanptr + 1) == '>'
token = PTRB_TKN
scanptr = scanptr + 2
else
token = SUB_TKN
scanptr = scanptr + 1
fin
break
is '>'
if ^(scanptr + 1) == '>'
token = SHR_TKN
scanptr = scanptr + 2
@ -2748,49 +2720,73 @@ def scan
scanptr = scanptr + 1
fin
break
is '='
if ^(scanptr + 1) == '='
token = EQ_TKN
scanptr = scanptr + 2
elsif ^(scanptr + 1) == '>'
token = PTRW_TKN
scanptr = scanptr + 2
else
token = SET_TKN
is '$'
//
// Hexadecimal constant
//
token = INT_TKN
constval = 0
repeat
scanptr = scanptr + 1
if ^scanptr >= '0' and ^scanptr <= '9'
constval = (constval << 4) + ^scanptr - '0'
elsif ^scanptr >= 'A' and ^scanptr <= 'F'
constval = (constval << 4) + ^scanptr - '7'// 'A'-10
elsif ^scanptr >= 'a' and ^scanptr <= 'f'
constval = (constval << 4) + ^scanptr - 'W'// 'a'-10
else
break
fin
until !^scanptr
break
is $27 // '
//
// Character constant
//
token = CHR_TKN
if ^(scanptr + 1) <> $5C // \
constval = ^(scanptr + 1)
if ^(scanptr + 2) <> $27 // '
return parse_err(@bad_cnst)
fin
scanptr = scanptr + 3
else
when ^(scanptr + 2)
is 'n'
constval = $0D; break
is 'r'
constval = $0A; break
is 't'
constval = $09; break
otherwise
constval = ^(scanptr + 2)
wend
if ^(scanptr + 3) <> $27 // '
return parse_err(@bad_cnst)
fin
scanptr = scanptr + 4
fin
break
is '"'
//
// String constant
//
token = STR_TKN
scanptr = scanptr + 1
constval = scanptr
while ^scanptr and ^scanptr <> '"'
scanptr = scanptr + 1
loop
if !^scanptr
return parse_err(@bad_cnst)
fin
scanptr = scanptr + 1
break
is '-'
if ^(scanptr + 1) == '>'
token = PTRB_TKN
scanptr = scanptr + 2
else
token = SUB_TKN
scanptr = scanptr + 1
fin
break
is '/'
if ^(scanptr + 1) == '/'
token = EOL_TKN
^scanptr = $00
else
token = DIV_TKN
scanptr = scanptr + 1
fin
break
is '~'
token = COMP_TKN
scanptr = scanptr + 1
break
is '|'
token = OR_TKN
scanptr = scanptr + 1
break
otherwise
//
// Simple single character tokens
//
token = ^scanptr | $80
token = scanchr | $80
scanptr = scanptr + 1
wend
fin