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simplify buffer handling in lexer

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Connor Olding 2015-11-26 18:49:01 -08:00
parent fa12154420
commit dc7f457b95
1 changed files with 26 additions and 37 deletions
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63
lips.lua
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@ -506,45 +506,39 @@ function Lexer:skip_to_EOL()
end
end
function Lexer:save_next()
self.buff = self.buff..self.chr
self:nextc()
end
function Lexer:read_chars(pattern)
local buff = ''
while string.find(self.chr, pattern) do
self:save_next()
buff = buff..self.chr
self:nextc()
end
return buff
end
function Lexer:read_decimal()
self.buff = ''
self:read_chars('%d')
local num = tonumber(self.buff)
local buff = self:read_chars('%d')
local num = tonumber(buff)
if not num then self:error('invalid decimal number') end
return num
end
function Lexer:read_hex()
self.buff = ''
self:read_chars('%x')
local num = tonumber(self.buff, 16)
local buff = self:read_chars('%x')
local num = tonumber(buff, 16)
if not num then self:error('invalid hex number') end
return num
end
function Lexer:read_octal()
self.buff = ''
self:read_chars('[0-7]')
local num = tonumber(self.buff)
local buff = self:read_chars('[0-7]')
local num = tonumber(buff)
if not num then self:error('invalid octal number') end
return num
end
function Lexer:read_binary()
self.buff = ''
self:read_chars('[01]')
local num = tonumber(self.buff, 2)
local buff = self:read_chars('[01]')
local num = tonumber(buff, 2)
if not num then self:error('invalid binary number') end
return num
end
@ -609,9 +603,8 @@ function Lexer:lex(yield)
self:nextc()
yield('SEP', ',')
elseif self.chr == '[' then
self.buff = ''
self:nextc()
self:read_chars('[%w_]')
local buff = self:read_chars('[%w_]')
if self.chr ~= ']' then
self:error('invalid define name')
end
@ -620,25 +613,23 @@ function Lexer:lex(yield)
self:error('define requires a colon')
end
self:nextc()
yield('DEF', self.buff)
yield('DEF', buff)
elseif self.chr == '(' then
self.buff = ''
self:nextc()
self:read_chars('[%w_]')
local buff = self:read_chars('[%w_]')
if self.chr ~= ')' then
self:error('invalid register name')
end
self:nextc()
local up = self.buff:upper()
local up = buff:upper()
if not all_registers[up] then
self:error('not a register')
end
yield('DEREF', up)
elseif self.chr == '.' then
self.buff = ''
self:nextc()
self:read_chars('[%w]')
local up = self.buff:upper()
local buff = self:read_chars('[%w]')
local up = buff:upper()
if not all_directives[up] then
self:error('not a directive')
end
@ -648,20 +639,18 @@ function Lexer:lex(yield)
yield('DIR', up)
end
elseif self.chr == '@' then
self.buff = ''
self:nextc()
self:read_chars('[%w_]')
yield('DEFSYM', self.buff)
local buff = self:read_chars('[%w_]')
yield('DEFSYM', buff)
elseif self.chr:find('[%a_]') then
self.buff = ''
self:read_chars('[%w_.]')
local up = self.buff:upper()
local buff = self:read_chars('[%w_.]')
local up = buff:upper()
if self.chr == ':' then
if self.buff:find('%.') then
if buff:find('%.') then
self:error('labels cannot contain dots')
end
self:nextc()
yield('LABEL', self.buff)
yield('LABEL', buff)
elseif up == 'HEX' then
yield('DIR', up)
elseif all_registers[up] then
@ -669,10 +658,10 @@ function Lexer:lex(yield)
elseif all_instructions[up] then
yield('INSTR', up:gsub('%.', '_'))
else
if self.buff:find('%.') then
if buff:find('%.') then
self:error('labels cannot contain dots')
end
yield('LABELSYM', self.buff)
yield('LABELSYM', buff)
end
elseif self.chr == ']' then
self:error('unmatched closing bracket')