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path: root/vendor/github.com/ijc/Gotty/parser.go
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Diffstat (limited to 'vendor/github.com/ijc/Gotty/parser.go')
-rw-r--r--vendor/github.com/ijc/Gotty/parser.go362
1 files changed, 362 insertions, 0 deletions
diff --git a/vendor/github.com/ijc/Gotty/parser.go b/vendor/github.com/ijc/Gotty/parser.go
new file mode 100644
index 000000000..a9d5d23c5
--- /dev/null
+++ b/vendor/github.com/ijc/Gotty/parser.go
@@ -0,0 +1,362 @@
+// Copyright 2012 Neal van Veen. All rights reserved.
+// Usage of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package gotty
+
+import (
+ "bytes"
+ "errors"
+ "fmt"
+ "regexp"
+ "strconv"
+ "strings"
+)
+
+var exp = [...]string{
+ "%%",
+ "%c",
+ "%s",
+ "%p(\\d)",
+ "%P([A-z])",
+ "%g([A-z])",
+ "%'(.)'",
+ "%{([0-9]+)}",
+ "%l",
+ "%\\+|%-|%\\*|%/|%m",
+ "%&|%\\||%\\^",
+ "%=|%>|%<",
+ "%A|%O",
+ "%!|%~",
+ "%i",
+ "%(:[\\ #\\-\\+]{0,4})?(\\d+\\.\\d+|\\d+)?[doxXs]",
+ "%\\?(.*?);",
+}
+
+var regex *regexp.Regexp
+var staticVar map[byte]stacker
+
+// Parses the attribute that is received with name attr and parameters params.
+func (term *TermInfo) Parse(attr string, params ...interface{}) (string, error) {
+ // Get the attribute name first.
+ iface, err := term.GetAttribute(attr)
+ str, ok := iface.(string)
+ if err != nil {
+ return "", err
+ }
+ if !ok {
+ return str, errors.New("Only string capabilities can be parsed.")
+ }
+ // Construct the hidden parser struct so we can use a recursive stack based
+ // parser.
+ ps := &parser{}
+ // Dynamic variables only exist in this context.
+ ps.dynamicVar = make(map[byte]stacker, 26)
+ ps.parameters = make([]stacker, len(params))
+ // Convert the parameters to insert them into the parser struct.
+ for i, x := range params {
+ ps.parameters[i] = x
+ }
+ // Recursively walk and return.
+ result, err := ps.walk(str)
+ return result, err
+}
+
+// Parses the attribute that is received with name attr and parameters params.
+// Only works on full name of a capability that is given, which it uses to
+// search for the termcap name.
+func (term *TermInfo) ParseName(attr string, params ...interface{}) (string, error) {
+ tc := GetTermcapName(attr)
+ return term.Parse(tc, params)
+}
+
+// Identify each token in a stack based manner and do the actual parsing.
+func (ps *parser) walk(attr string) (string, error) {
+ // We use a buffer to get the modified string.
+ var buf bytes.Buffer
+ // Next, find and identify all tokens by their indices and strings.
+ tokens := regex.FindAllStringSubmatch(attr, -1)
+ if len(tokens) == 0 {
+ return attr, nil
+ }
+ indices := regex.FindAllStringIndex(attr, -1)
+ q := 0 // q counts the matches of one token
+ // Iterate through the string per character.
+ for i := 0; i < len(attr); i++ {
+ // If the current position is an identified token, execute the following
+ // steps.
+ if q < len(indices) && i >= indices[q][0] && i < indices[q][1] {
+ // Switch on token.
+ switch {
+ case tokens[q][0][:2] == "%%":
+ // Literal percentage character.
+ buf.WriteByte('%')
+ case tokens[q][0][:2] == "%c":
+ // Pop a character.
+ c, err := ps.st.pop()
+ if err != nil {
+ return buf.String(), err
+ }
+ buf.WriteByte(c.(byte))
+ case tokens[q][0][:2] == "%s":
+ // Pop a string.
+ str, err := ps.st.pop()
+ if err != nil {
+ return buf.String(), err
+ }
+ if _, ok := str.(string); !ok {
+ return buf.String(), errors.New("Stack head is not a string")
+ }
+ buf.WriteString(str.(string))
+ case tokens[q][0][:2] == "%p":
+ // Push a parameter on the stack.
+ index, err := strconv.ParseInt(tokens[q][1], 10, 8)
+ index--
+ if err != nil {
+ return buf.String(), err
+ }
+ if int(index) >= len(ps.parameters) {
+ return buf.String(), errors.New("Parameters index out of bound")
+ }
+ ps.st.push(ps.parameters[index])
+ case tokens[q][0][:2] == "%P":
+ // Pop a variable from the stack as a dynamic or static variable.
+ val, err := ps.st.pop()
+ if err != nil {
+ return buf.String(), err
+ }
+ index := tokens[q][2]
+ if len(index) > 1 {
+ errorStr := fmt.Sprintf("%s is not a valid dynamic variables index",
+ index)
+ return buf.String(), errors.New(errorStr)
+ }
+ // Specify either dynamic or static.
+ if index[0] >= 'a' && index[0] <= 'z' {
+ ps.dynamicVar[index[0]] = val
+ } else if index[0] >= 'A' && index[0] <= 'Z' {
+ staticVar[index[0]] = val
+ }
+ case tokens[q][0][:2] == "%g":
+ // Push a variable from the stack as a dynamic or static variable.
+ index := tokens[q][3]
+ if len(index) > 1 {
+ errorStr := fmt.Sprintf("%s is not a valid static variables index",
+ index)
+ return buf.String(), errors.New(errorStr)
+ }
+ var val stacker
+ if index[0] >= 'a' && index[0] <= 'z' {
+ val = ps.dynamicVar[index[0]]
+ } else if index[0] >= 'A' && index[0] <= 'Z' {
+ val = staticVar[index[0]]
+ }
+ ps.st.push(val)
+ case tokens[q][0][:2] == "%'":
+ // Push a character constant.
+ con := tokens[q][4]
+ if len(con) > 1 {
+ errorStr := fmt.Sprintf("%s is not a valid character constant", con)
+ return buf.String(), errors.New(errorStr)
+ }
+ ps.st.push(con[0])
+ case tokens[q][0][:2] == "%{":
+ // Push an integer constant.
+ con, err := strconv.ParseInt(tokens[q][5], 10, 32)
+ if err != nil {
+ return buf.String(), err
+ }
+ ps.st.push(con)
+ case tokens[q][0][:2] == "%l":
+ // Push the length of the string that is popped from the stack.
+ popStr, err := ps.st.pop()
+ if err != nil {
+ return buf.String(), err
+ }
+ if _, ok := popStr.(string); !ok {
+ errStr := fmt.Sprintf("Stack head is not a string")
+ return buf.String(), errors.New(errStr)
+ }
+ ps.st.push(len(popStr.(string)))
+ case tokens[q][0][:2] == "%?":
+ // If-then-else construct. First, the whole string is identified and
+ // then inside this substring, we can specify which parts to switch on.
+ ifReg, _ := regexp.Compile("%\\?(.*)%t(.*)%e(.*);|%\\?(.*)%t(.*);")
+ ifTokens := ifReg.FindStringSubmatch(tokens[q][0])
+ var (
+ ifStr string
+ err error
+ )
+ // Parse the if-part to determine if-else.
+ if len(ifTokens[1]) > 0 {
+ ifStr, err = ps.walk(ifTokens[1])
+ } else { // else
+ ifStr, err = ps.walk(ifTokens[4])
+ }
+ // Return any errors
+ if err != nil {
+ return buf.String(), err
+ } else if len(ifStr) > 0 {
+ // Self-defined limitation, not sure if this is correct, but didn't
+ // seem like it.
+ return buf.String(), errors.New("If-clause cannot print statements")
+ }
+ var thenStr string
+ // Pop the first value that is set by parsing the if-clause.
+ choose, err := ps.st.pop()
+ if err != nil {
+ return buf.String(), err
+ }
+ // Switch to if or else.
+ if choose.(int) == 0 && len(ifTokens[1]) > 0 {
+ thenStr, err = ps.walk(ifTokens[3])
+ } else if choose.(int) != 0 {
+ if len(ifTokens[1]) > 0 {
+ thenStr, err = ps.walk(ifTokens[2])
+ } else {
+ thenStr, err = ps.walk(ifTokens[5])
+ }
+ }
+ if err != nil {
+ return buf.String(), err
+ }
+ buf.WriteString(thenStr)
+ case tokens[q][0][len(tokens[q][0])-1] == 'd': // Fallthrough for printing
+ fallthrough
+ case tokens[q][0][len(tokens[q][0])-1] == 'o': // digits.
+ fallthrough
+ case tokens[q][0][len(tokens[q][0])-1] == 'x':
+ fallthrough
+ case tokens[q][0][len(tokens[q][0])-1] == 'X':
+ fallthrough
+ case tokens[q][0][len(tokens[q][0])-1] == 's':
+ token := tokens[q][0]
+ // Remove the : that comes before a flag.
+ if token[1] == ':' {
+ token = token[:1] + token[2:]
+ }
+ digit, err := ps.st.pop()
+ if err != nil {
+ return buf.String(), err
+ }
+ // The rest is determined like the normal formatted prints.
+ digitStr := fmt.Sprintf(token, digit.(int))
+ buf.WriteString(digitStr)
+ case tokens[q][0][:2] == "%i":
+ // Increment the parameters by one.
+ if len(ps.parameters) < 2 {
+ return buf.String(), errors.New("Not enough parameters to increment.")
+ }
+ val1, val2 := ps.parameters[0].(int), ps.parameters[1].(int)
+ val1++
+ val2++
+ ps.parameters[0], ps.parameters[1] = val1, val2
+ default:
+ // The rest of the tokens is a special case, where two values are
+ // popped and then operated on by the token that comes after them.
+ op1, err := ps.st.pop()
+ if err != nil {
+ return buf.String(), err
+ }
+ op2, err := ps.st.pop()
+ if err != nil {
+ return buf.String(), err
+ }
+ var result stacker
+ switch tokens[q][0][:2] {
+ case "%+":
+ // Addition
+ result = op2.(int) + op1.(int)
+ case "%-":
+ // Subtraction
+ result = op2.(int) - op1.(int)
+ case "%*":
+ // Multiplication
+ result = op2.(int) * op1.(int)
+ case "%/":
+ // Division
+ result = op2.(int) / op1.(int)
+ case "%m":
+ // Modulo
+ result = op2.(int) % op1.(int)
+ case "%&":
+ // Bitwise AND
+ result = op2.(int) & op1.(int)
+ case "%|":
+ // Bitwise OR
+ result = op2.(int) | op1.(int)
+ case "%^":
+ // Bitwise XOR
+ result = op2.(int) ^ op1.(int)
+ case "%=":
+ // Equals
+ result = op2 == op1
+ case "%>":
+ // Greater-than
+ result = op2.(int) > op1.(int)
+ case "%<":
+ // Lesser-than
+ result = op2.(int) < op1.(int)
+ case "%A":
+ // Logical AND
+ result = op2.(bool) && op1.(bool)
+ case "%O":
+ // Logical OR
+ result = op2.(bool) || op1.(bool)
+ case "%!":
+ // Logical complement
+ result = !op1.(bool)
+ case "%~":
+ // Bitwise complement
+ result = ^(op1.(int))
+ }
+ ps.st.push(result)
+ }
+
+ i = indices[q][1] - 1
+ q++
+ } else {
+ // We are not "inside" a token, so just skip until the end or the next
+ // token, and add all characters to the buffer.
+ j := i
+ if q != len(indices) {
+ for !(j >= indices[q][0] && j < indices[q][1]) {
+ j++
+ }
+ } else {
+ j = len(attr)
+ }
+ buf.WriteString(string(attr[i:j]))
+ i = j
+ }
+ }
+ // Return the buffer as a string.
+ return buf.String(), nil
+}
+
+// Push a stacker-value onto the stack.
+func (st *stack) push(s stacker) {
+ *st = append(*st, s)
+}
+
+// Pop a stacker-value from the stack.
+func (st *stack) pop() (stacker, error) {
+ if len(*st) == 0 {
+ return nil, errors.New("Stack is empty.")
+ }
+ newStack := make(stack, len(*st)-1)
+ val := (*st)[len(*st)-1]
+ copy(newStack, (*st)[:len(*st)-1])
+ *st = newStack
+ return val, nil
+}
+
+// Initialize regexes and the static vars (that don't get changed between
+// calls.
+func init() {
+ // Initialize the main regex.
+ expStr := strings.Join(exp[:], "|")
+ regex, _ = regexp.Compile(expStr)
+ // Initialize the static variables.
+ staticVar = make(map[byte]stacker, 26)
+}
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-09-26 21:53:36 +0000